The interpretation timeline
Psalm 138:8 Douay-Rheims

If I ascend into heaven, thou art there: if I descend into hell, thou art present.

A.D. 99 – 1875 10 witnesses 13 excerpts

Patristic

before A.D. 750
99
A.D.
Clement of Rome Patristic
d. A.D. 99
“Since, therefore, all things are seen and heard, let us fear him and abandon the abominable lusts that spawn evil works, in order that we may be shielded by his mercy from the coming judgments. For where can any of us escape from his mighty hand? For the Scripture says somewhere, "Where shall I go, and where shall I be hidden from your presence? If I ascend to heaven, you are there; if I depart to the ends of the earth, there is your right hand; if I take my bed in the depths, there is your Spirit." Where, then, can one go, or where can one flee from him who embraces the universe?”
Source
367
A.D.
Hilary of Poitiers Patristic
c. A.D. 310–367
“My mind, intent on the study of truth, took delight in these most pious teachings about God. For it did not consider any other thing worthy of God than that he is so far beyond the power of comprehension that the more the infinite spirit would endeavor to encompass him to any degree, even though it be by an arbitrary assumption, the more the infinity of a measureless eternity would surpass the entire infinity of the nature that pursues it. Although we understood this teaching in a reverent manner, it was clearly confirmed by these words of the prophet: "Whither shall I go from your spirit? Or whither shall I flee from your face? If I ascend into heaven, you are there; if I descend into hell, you are present. If I take my wings early in the morning and dwell in the uttermost parts of the sea, even there also shall your hand lead me and your right hand shall hold me." There is no place without God, nor is there any place which is not in God. He is in heaven, in hell and beyond the seas. He is within all things; he comes forth and is outside all things. While he thus possesses and is possessed, he is not included in anything nor is he not in all things.”
Source
379
A.D.
Basil of Caesarea Patristic
c. A.D. 330–379
“If they really conceive of a kind of subordination of the Son in relation to the Father, as though he were in a lower place, so that the Father sits above and the Son is thrust off to the next seat below, let them confess what they mean. We shall have no more to say. A plain statement of the view will at once expose its absurdity. They who refuse to allow that the Father pervades all things do not so much as maintain the logical sequence of thought in their argument. The faith of the orthodox is that God fills all things; but they who divide their up and down between the Father and the Son do not remember even the word of the prophet: "If I climb up into heaven, you are there; if I go down to hell, you are there also." Now, to omit all proof of the ignorance of those who predicate place of incorporeal things, what excuse can be found for their attack upon Scripture, shameless as their antagonism is, in the passages "Sit on my right hand" and "Sat down on the right hand of the majesty of God"? The expression "right hand" does not, as they contend, indicate the lower place, but equality of relation; it is not understood physically, in which case there might be something sinister about God, but Scripture puts before us the magnificence of the dignity of the Son by the use of dignified language indicating the seat of honor. It is left then for our opponents to allege that this expression signifies inferiority of rank. Let them learn that "Christ is the power of God and wisdom of God," and that "he is the image of the invisible God" and "brightness of his glory" and that "him has God the Father sealed," by engraving himself on him.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“"...if our heart think ill of us," i.e. accuse us within, that we do not the thing with that mind it ought to be done withal, "greater is God than our heart, and knoweth all things." Thou hidest thine heart from man: hide it from God if thou canst! How shalt thou hide it from Him, to whom it is said by a sinner, fearing and confessing, "Whither shall I go from Thy Spirit? and from Thy face whither shall I flee?" He sought a way to flee, to escape the judgment of God, and found none. For where is God not? "If I shall ascend," saith he, "into heaven, Thou art there: if I shall descend into hell, Thou art there." Whither wilt thou go? whither wilt thou flee? Wilt thou hear counsel? If thou wouldest flee from Him, flee to Him. Flee to Him by confessing, not from Him by hiding: hide thou canst not, but confess thou canst. Say unto Him, "Thou art my place to flee unto," and let love be nourished in thee, which alone leadeth unto life. Let thy conscience bear thee witness that thy love is of God. If it be of God, do not wish to display it before men; because neither men's praises lift thee unto heaven, nor their censures put thee down from thence. Let Him see, who crowneth thee: be He thy witness, by whom as judge thou art crowned. "Greater is God than our heart, and knoweth all things."”
Source
“...whither was He sent except to the place where He already was? For He who says, "I fill heaven and earth," was everywhere. But if it is said of the Father, where could He be without His own word and without His own wisdom, which "reacheth from one end to another mightily, and sweetly ordereth all things?" But He cannot be anywhere without His own Spirit. Therefore, if God is everywhere, His Spirit also is everywhere. Therefore, the Holy Spirit, too, was sent thither, where He already was. For he, too, who finds no place to which he might go from the presence of God, and who says, "If I ascend up into heaven, Thou art there; if I shall go down into hell, behold, Thou art there;" wishing it to be understood that God is present everywhere, named in the previous verse His Spirit; for He says, "Whither shall I go from Thy Spirit? or whither shall I flee from Thy presence?"”
Source
“"If I go up," says he, "to heaven, You are there: if I go down to Hades, You are present" [Psalm 139:8]. At length, miserable runaway, you have learned, that by no means can you make yourself far from Him, from whom you have wished to remove far away. Behold, He is everywhere; thou, whither will you go? He has found counsel, and that inspired by Him, who now deigns to recall him....If by sinning I go down to the depths of wickednesses, and spurn to confess, saying, "Who sees me" (for "in Hades who shall confess to You?" ) there also You are present, to punish. Whither then shall I go that I may flee from Your presence, that is, not find You angry? This plan he found: So will I flee, says he, from Your Face, so will I flee from Your Spirit; from Your avenging Spirit, Your avenging Face thus will I flee.”
Source
“For this reason, of course, it was not enough for Jesus to say, "I will that where I am they also may be," but he added, "with me." For to be with him is a great good. For even the wretched can be where he is because wherever anybody at all may be [there] he also is; but the blessed alone are with him, because they will be unable to be blessed except by his action. Or has it not been truly said to God, "If I ascend into heaven, you are there; and if I descend into hell, you are present"? Or on the other hand is Christ not God's Wisdom, which "reaches everywhere by reason of its purity"?”
Source
date
unknown
c. A.D. 550
“For Deity alone is uncircumscribed, existing everywhere, and as the same and in the same manner. For if I ascend, saith David, into heaven, thou art there; if I descend into Hades thou art present there; if I should take to myself wings at morning—that is, in the east—and dwell in the uttermost parts of the sea—that is, in the west—even there shall thy hand lead me: evidently indicating here the uncircumscribed nature of the Deity”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“and if I make my bed Heb. ואציעה, an expression of a spread (מצע) and a bed.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“If I take the wings of the morning,.... And fly as swift as the morning light to the east, to the extremity of it, as Ben Melech; as far as he could go that way, as swiftly as the wings of the morning could carry him thither; so the morning is represented by the Heathens as having wings (f); or as the rays of the rising sun, called wings for the swiftness of them, Mal 4:2; and dwell in the uttermost parts of the sea; in the most distant isles of it, in the farthest parts of the world, the sea being supposed the boundary of it: or "in the uttermost parts of the west" (g), as opposed to the morning light and rising sun, which appear in the east; and the sea is often in Scripture put for the west, the Mediterranean sea being to the west of the land of Palestine; and could he go from east to west in a moment, as the above writer observes, there would God be. The Heathens represent Jupiter, their supreme god, as having three eyes, because he reigns in heaven, and in earth, and under the earth (h). (f) Vid. Cuperi Apotheos. Homeri, p. 177. (g) "in novissimo occidentis", Pagninus. (h) Pausan. Corinthiaca, sive l. 2. p. 129.”
Source
1849
A.D.
1774–1849
“Descend. Hebrew, “make my bed the grave or hell,” Job xvii. 13. The living and the dead are equally in God’s power. (Calmet)”
1863
A.D.
1875
A.D.
Keil & Delitzsch Lutheran
1861–1875
“The future form אסּק, customary in the Aramaic, may be derived just as well from סלק (סלק), by means of the same mode of assimilation as in יסּב = יסבּב, as from נסק (נסק), which latter is certainly only insecurely established by Dan 6:24, להנסקה (cf. להנזקת, Ezr 4:22; הנפּק, Dan 5:2), since the Nun, as in להנעלה, Dan 4:3, can also be a compensation for the resolved doubling (vid., Bernstein in the Lexicon Chrestom. Kirschianae, and Levy s.v. נסק). אם with the simple future is followed by cohortatives (vid., on Psa 73:16) with the equivalent אשּׂא among them: et si stratum facerem (mihi) infernum (accusative of the object as in Isa 58:5), etc. In other passages the wings of the sun (Mal 4:2) and of the wind (Psa 18:11) are mentioned, here we have the wings of the morning's dawn. Pennae aurorae, Eugubinus observes (1548), est velocissimus aurorae per omnem mundum decursus. It is therefore to be rendered: If I should lift wings (נשׂא כנפים as in Eze 10:16, and frequently) such as the dawn of the morning has, i.e., could I fly with the swiftness with which the dawn of the morning spreads itself over the eastern sky, towards the extreme west and alight there. Heaven and Hades, as being that which is superterrestrial and subterrestrial, and the east and west are set over against one another. אחרית ים is the extreme end of the sea (of the Mediterranean with the "isles of the Gentiles"). In Psa 139:10 follows the apodosis: nowhere is the hand of God, which governs everything, to be escaped, for dextera Dei ubique est. ואמר (not ואמר, Eze 13:15), "therefore I spake," also has the value of a hypothetical protasis: quodsi dixerim. אך and חשׁך belongs together: merae tenebrae (vid: Psa 39:6.); but ישׁוּפני is obscure. The signification secured to it of conterere, contundere, in Gen 3:15; Job 9:17, which is followed by the lxx (Vulgate) καταπατήσει, is inappropriate to darkness. The signification inhiare, which may be deduced as possible from שׁאף, suits relatively better, yet not thoroughly well (why should it not have been יבלעני?). The signification obvelare, however, which one expects to find, and after which the Targum, Symmachus, Jerome, Saadia, and others render it, seems only to be guessed at from the connection, since שׁוּף has not this signification in any other instance, and in favour of it we cannot appeal either to נשׁף - whence נשׁף, which belongs together with נשׁב, נשׁם, and נפשׁ - or to עטף, the root of which is עת (עתה), or to צעף, whence צעיף, which does not signify to cover, veil, but according to Arab. ḍ‛f, to fold, fold together, to double. We must therefore either assign to ישׁוּפני the signification operiat me without being able to prove it, or we must put a verb of this signification in its place, viz., ישׂוּכני (Ewald) or יעוּפני (Bttcher), which latter is the more commendable here, where darkness (חשׁך, synon. עיפה, מעוּף) is the subject: and if I should say, let nothing but darkness cover me, and as night (the predicate placed first, as in Amo 4:13) let the light become about me, i.e., let the light become night that shall surround and cover me (בּעדני, poetic for בּעדי, like תּחתּני in 2 Sam. 22) - the darkness would spread abroad no obscurity (Psa 105:28) that should extend beyond (מן) Thy piercing eye and remove me from Thee. In the word יאיר, too, the Hiphil signification is not lost: the night would give out light from itself, as if it were the day; for the distinction of day and night has no conditioning influence upon God, who is above and superior to all created things (der Uebercreatrliche), who is light in Himself. The two כ are correlative, as e.g., in Kg1 22:4. חשׁיכה (with a superfluous Jod) is an old word, but אורה (cf. Aramaic אורתּא) is a later one.”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.