The interpretation timeline
Luke 2:15 Douay-Rheims

And it came to pass, after the angels departed from them into heaven, the shepherds said one to another: Let us go over to Bethlehem, and let us see this word that is come to pass, which the Lord hath shewed to us.

A.D. 253 – 1871 10 witnesses 18 excerpts

Patristic

before A.D. 750
253
A.D.
Origen Patristic
c. A.D. 184–253
“That was the manger which Israel knew not, according to those words of Isaiah, The ox knoweth his owner, and the ass his master’s crib. (Isa. 3:1.)”
397
A.D.
Ambrose of Milan Patristic
A.D. 339–397
“How remarkably Scripture weighs the import of each word. For when we behold the flesh of the Lord, we behold the Word, which is the Son. Let not this seem to you a slight example of faith, because of the humble character of the shepherds. For simplicity is sought for, not pride. It follows, And they came in haste. For no one indolently seeks after Christ.”
Source
735
A.D.
Bede the Venerable Patristic
c. A.D. 672–735
“As men who were truly watching, they said not, Let us see (the child; but) the word which has come to pass, i. e. the Word which was from the beginning, let us see how it has been made flesh for us. since this very Word is the Lord. For it follows, Which the Lord hath made, and has shewn to us; i. e. Let us see how the Lord hath made Himself, and hath shewn His flesh to us.”
Source
“(Hom. ubi sup.) For keeping the laws of virgin modesty, she who had known the secrets of Christ would divulge them to no one, but comparing what she had read in prophecy with what she now acknowledged to have taken place, she did not utter them with the mouth, but preserved them shut up in her heart.”
“That is to say, from the Angels, and had seen, i. e. in Bethlehem, as it was told them, i. e. they glory in this, that when they came they found it even as it was told them, or as it was told them they give praise and glory to God. For this they were told by the Angels to do, not in very word commanding them, but setting before them the form of devotion when they sung glory to God in the highest.”
Source
“(Hom. ubi sup.) To speak in a mystery, let the shepherds of spiritual flocks, (nay, all the faithful,) after the example of these shepherds, go in thought even to Bethlehem, and celebrate the incarnation of Christ with due honours. Let us go indeed casting aside all fleshly lusts, with the whole desire of the mind even to the heavenly Bethlehem, (i. e. the house of the living bread,) that He whom they saw crying in the manger we may deserve to see reigning on the throne of His Father. And such bliss as this is not to be sought for with sloth and idleness, but with eagerness must we follow the footsteps of Christ. When they saw Him they knew Him; and let us haste to embrace in the fulness of our love those things which were spoken of our Saviour, that When the time shall come that we shall see with perfect knowledge we may be able to comprehend them.”
Source
“(Hom. ubi sup.) The shepherds did not hide in silence what they knew, because to this end have the Shepherds of the Church been ordained, that what they have learned in the Scriptures they might explain to their hearers.”
“(in loc.) The masters of the spiritual flocks also, while others sleep, at one time by contemplation enter into the heavenly places, at another time pass around them by seeking the examples of the faithful, at another time by teaching return to the public duties of the pastoral office.”
“(Hom. ubi sup.) Every one of us, even he who is supposed to live as a private person, exercises the office of shepherd, if, keeping together a multitude of good actions and pure thoughts, he strive to rule them with due moderation, to feed them with the food of the Scriptures, and to preserve them against the snares of the devil.”
Source

Reformation

c. 1500 – 1650
1637
A.D.
1567–1637
“And it came to pass, as the angels were gone away from them into heaven , the shepherds said one to another , Let us now go even unto Bethlehem, and see this thing which is come to pass . This thing a metonomy, common in Scripture, by which the word is put for the thing signified by it, as in ch. L 37, “No word ” — that is, nothing “shall be impossible with God.” And in 2 Kings i. 4, “ What is the word that is come to pass ? ” Which the Lord hath made known unto us . In the Greek tywotoi — revealed, made known Yea, and has given us, rather than the scribes and all others, a sign by which we shall find the Messiah that is born. Wherefore, if we, who have been invited by Him through an angel, do not visit and adore Him who is born for us, and revealed first to us, we shall be ungrateful to God, to the angels, and to Christ, and enemies to ourselves”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“And it came to pass, as the angels,.... The Persic version reads in the singular number, "the angel: were gone away from them into heaven", from whence they came, and which was the place of their abode and residence; and therefore they are called the angels of heaven, where they always behold the face of God, hearken to the voice of his commandment, and go and come at his orders; and these having finished their embassy, delivered their message to the shepherds, and done all the work they came about, departed from them: and, as the Ethiopic version adds, "and ascended up into heaven"; and as soon as they were gone, immediately, the shepherds said one to another, let us now go even to Bethlehem the place where the angel said the Saviour was born, and see this thing which hath come to pass, which the Lord hath made known to us: from whence it appears, that it was not from diffidence of the matter, as questioning the truth of what the angel said, that they moved one another to go to Bethlehem; for they firmly believed the thing was come to pass, which the angel had told them of, and that what he said was from the Lord; nor did they act any criminal part, or indulge a vain curiosity, in going to Bethlehem to see what was done; for it seems to be the will of God that they should go, and for which they had a direction from the angel, and a sign given them by which they might know the new born Saviour from any other infant, Luk 2:12 and which would also be a further confirmation of their faith, and by which they would be qualified not only as ear, but as eyewitnesses of the truth of this fact, to report it with greater certainty.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Let us now go even unto Bethlehem - Διελθωμεν, let us go across the country at the nearest, that we may lose no time, that we may speedily see this glorious reconciler of God and man. All delays are dangerous: but he who delays to seek Jesus, when the angels, the messengers of God, bring him glad tidings of salvation, risks his present safety and his eternal happiness. O, what would the damned in hell give for those moments in which the living hear of salvation, had they the same possibility of receiving it! Reader, be wise. Acquaint thyself now with God, and be at peace; and thereby good will come unto thee. Amen.”
Source
1849
A.D.
1774–1849
“The word which always was, let us see how it is made for us; that which we could not see, when it was the word, let us see because it is made flesh. (Ven. Bede) — See how particularly the Scripture weighs the meaning of every word. The shepherds hastened to see the word, for when the flesh of the Lord is seen, the word is seen, which is the Son. (St. Ambrose)”
Source
1871
A.D.
1871
“Let us go, &c.--lovely simplicity of devoutness and faith this! They are not taken up with the angels, the glory that invested them, and the lofty strains with which they filled the air. Nor do they say, Let us go and see if this be true--they have no misgivings. But "Let us go and see this thing which is come to pass, which the Lord hath made known unto us." Does not this confirm the view given on Luk 2:8 of the spirit of these humble men?”
Source

Undated

date unknown
date
unknown
“(Geometer.) The shepherds were filled with astonishment at the things that they saw and heard, and so they left their sheep-folds, and set out by night to Bethlehem, seeking for the light of the Saviour; and therefore it is said, They spoke one to another, &c.”
“(Photius) Beholding with hidden faith indeed the happy events which had been told them, and not content with marvelling at the reality of those things which at the very first they saw and embraced when the Angel told them, they began to relate them not only to Mary and Joseph, but to the others also, (and what is more they impressed them on their minds,) as it follows, And all who heard it marvelled. For how could it be otherwise, at the sight of one of the heavenly host upon earth, and earth in peace reconciled to heaven; and that ineffable Child binding together in one, by His divinity, heavenly things, by His humanity, earthly things, and by this conjunction of Himself effecting a wonderful union!”
Source
date
unknown
Glossa Ordinaria Medieval
“Not only do they marvel at the mystery of the incarnation, but also at so wonderful an attestation of the shepherds, men who could not have devised these unheard of things, but were with simple eloquence proclaiming the truth.”
date
unknown
“(Metaphrastes) Whatever the Angel had said unto her, whatever she had heard from Zacharias, and Elisabeth, and the shepherds, she collected them all in her mind, and comparing them together, perceived in all one harmony. Truly, He was God who was born from her.”
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.