The interpretation timeline
Psalm 66:2 Douay-Rheims

May God have mercy on us, and bless us: may he cause the light of his countenance to shine upon us, and may he have mercy on us.

A.D. 430 – 1871 5 witnesses 6 excerpts

Patristic

before A.D. 750
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“This, I say, is the universal way for the deliverance of believers, concerning which the faithful Abraham received the divine assurance, "In thy seed shall all nations be blessed." He, indeed, was by birth a Chaldaean; but, that he might receive these great promises, and that there might be propagated from him a seed "disposed by angels in the hand of a Mediator," in whom this universal way, thrown open to all nations for the deliverance of the soul, might be found, he was ordered to leave his country, and kindred, and father's house. Then was he himself, first of all, delivered from the Chaldaean superstitions, and by his obedience worshipped the one true God, whose promises he faithfully trusted. This is the universal way, of which it is said in holy prophecy, "God be merciful unto us, and bless us, and cause his face to shine upon us; that thy way may be known upon earth, thy saving health among all nations." And hence, when our Savior, so long after, had taken flesh of the seed of Abraham, he says of himself, "I am the way, the truth, and the life."”
Source
“"That we may know on earth Thy way" [Psalm 67:2]. "On earth," here, in this life, "we may know Thy way." What is, "Thy way"? That which leadeth to Thee. May we acknowledge whither we are going, acknowledge where we are as we go; neither in darkness we can do. Afar Thou art from men sojourning, a way to us Thou hast presented, through which we must return to Thee. "Let us acknowledge on earth Thy way." What is His way wherein we have desired, "That we may know on earth Thy way"? We are going to enquire this ourselves, not of ourselves to learn it. We can learn of it from the Gospel: "I am the Way," [John 14:6] the Lord saith: Christ hath said, "I am the Way." But dost thou fear lest thou stray? He hath added, "And the Truth." Who strayeth in the Truth? He strayeth that hath departed from the Truth. The Truth is Christ, the Way is Christ: walk therein. Dost thou fear lest thou die before thou attain unto Him? "I am the Life: I am," He saith, "the Way and the Truth and the Life." As if He were saying, "What fearest thou? Through Me thou walkest, to Me thou walkest, in Me thou restest." What therefore meaneth, "We may know on earth Thy Way," but "we may know on earth Thy Christ"? But let the Psalm itself reply: lest ye think that out of other Scriptures there must be adduced testimony, which perchance is here wanting: by repetition he hath shown what signified, "That we may know on earth Thy Way:" and as if thou wast inquiring, "In what earth, what way?" "In all nations Thy Salvation." In what earth, thou art inquiring? Hear: "In all nations." What way art thou seeking? Hear: "Thy Salvation." Is not perchance Christ his Salvation? And what is that which the old Symeon hath said, that old man, I say, in the Gospel, preserved full of years even unto the infancy of the Word? For that old man took in his hands the Infant Word of God. Would He that in the womb deigned to be, disdain to be in the hands of an old man? The Same was in the womb of the virgin, as was in the hands of the old man, a weak infant both within the bowels, and in the old man's hand, to give us strength, by whom were made all things; and if all things, even His very mother. He came humble, He came weak, but clothed with a weakness to be changed into strength, because "though He was crucified of weakness, yet He liveth of the virtue of God," [2 Corinthians 13:4] the Apostle saith. He was then in the hands of an old man. And what saith that old man? Rejoicing that now he must be loosed from this world, seeing how in his own hand was held He by whom and in whom his Salvation was upheld; he saith what? "Now Thou lettest go," he saith, "O Lord, Thy servant in peace, for mine eyes have seen Thy Salvation." [Luke 2:29-30] Therefore, "May God bless us, and have pity on us; may He lighten His countenance upon us, that we may know on earth Thy Way!" In what earth? "In all nations." What Way? "Thy Salvation."”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“He will cause His countenance to shine To show a laughing countenance, to give dew and rain.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“That thy way may be known upon earth,.... God's way and method of grace, in the salvation of sinners; the contrivance of it in Christ, the impetration of it by him, and the application of it by his Spirit; and the way of sinners to him through Christ, the way, the truth, and the life, the new and living way to the Father; and the way of life and salvation, which is grace, and by Christ alone; and the Gospel which points out this way, and is itself called the way of God, Act 18:25; together with the ordinances of it, which are ways of pleasantness, and paths of peace; all this was made known by the apostles and first preachers of the Gospel; not only in the land of Judea, but throughout the whole earth; thy saving health among all nations; or "thy salvation"; or "thy Jesus" (l); whose name signifies a Saviour; and who is the only one, and an able and willing one, and is God's salvation, of his appointing, promising, and sending; salvation is by him, and by him only; he came to obtain it, and he is the author of it; health is also by him, he is the physician of souls, and his blood the balm that cures every disease; so that he is the Saviour, salvation, and saving health, to his people; this was unknown to the nations of the world until the Gospel came among them, until the grace of God bringing this salvation appeared unto them, and shone upon them, Tit 2:11. (l) "salutem tuam", Pagninus, Montanus, &c. "i.e. salvatorem cujus nomen erit Jesus", Gejerus.”
Source
1849
A.D.
1774–1849
“Upon us, to grant our requests; or may the Messias come, Hebrews i. 3. — And may, &c., is in the Arabic, and in most copies of the Septuagint and Vulgate, though it is omitted in Hebrew, &c., “and we shall live.” (Ethiopic) (Calmet) — Perhaps it may be given to express the sense of Selah, which seems to have been a term of approbation. It does not alter the sense. (Berthier) — God first forgives sins, and then bestows his manifold graces. (Worthington) — This was the form of solemn blessing, Numbers vi. 17. (Du Hamel)”
Source
1871
A.D.
1871
“thy way--of gracious dealing (Isa 55:8), as explained by-- saving health--or literally, "salvation."”
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.