The interpretation timeline
Genesis 16:15 Douay-Rheims

And Agar brought forth a son to Abram: who called his name Ismael.

A.D. 430 – 1875 8 witnesses

Patristic

before A.D. 750
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“There was indeed on earth, so long as it was needed, a symbol and foreshadowing image of this city, which served the purpose of reminding men that such a city was to be rather than of making it present; and this image was itself called the holy city, as a symbol of the future city, though not itself the reality. Of this city which served as an image, and of that free city it typified, Paul writes to the Galatians in these terms: "Tell me, you that desire to be under the law, do you not hear the law? For it is written, that Abraham had two sons, the one by a bond maid, the other by a free woman. But he who was of the bond woman was born after the flesh, but he of the free woman was by promise. Which things are an allegory: for these are the two covenants; the one from the mount Sinai, which genders to bondage, which is Agar. For this Agar is mount Sinai in Arabia, and answers to Jerusalem which now is, and is in bondage with her children. But Jerusalem which is above is free, which is the mother of us all. For it is written, Rejoice, you barren that bear not; break forth and cry, you that travail not, for the desolate has many more children than she which has an husband. Now we, brethren, as Isaac was, are the children of promise. But as then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now. Nevertheless, what says the Scripture? Cast out the bond woman and her son: for the son of the bond woman shall not be heir with the son of the free woman. And we, brethren, are not children of the bond woman, but of the free, in the liberty wherewith Christ has made us free." [Galatians 4:21-31] This interpretation of the passage, handed down to us with apostolic authority, shows how we ought to understand the Scriptures of the two covenants — the old and the new. One portion of the earthly city became an image of the heavenly city, not having a significance of its own, but signifying another city, and therefore serving, or "being in bondage." For it was founded not for its own sake, but to prefigure another city; and this shadow of a city was also itself foreshadowed by another preceding figure. For Sarah's handmaid Agar, and her son, were an image of this image. And as the shadows were to pass away when the full light came, Sarah, the free woman, who prefigured the free city (which again was also prefigured in another way by that shadow of a city Jerusalem), therefore said, "Cast out the bond woman and her son; for the son of the bond woman shall not be heir with my son Isaac," or, as the apostle says, "with the son of the free woman." In the earthly city, then, we find two things — its own obvious presence, and its symbolic presentation of the heavenly city. Now citizens are begotten to the earthly city by nature vitiated by sin, but to the heavenly city by grace freeing nature from sin; whence the former are called "vessels of wrath," the latter "vessels of mercy." [Romans 9:22-23] And this was typified in the two sons of Abraham — Ishmael, the son of Agar the handmaid, being born according to the flesh, while Isaac was born of the free woman Sarah, according to the promise. Both, indeed, were of Abraham's seed; but the one was begotten by natural law, the other was given by gracious promise. In the one birth, human action is revealed; in the other, a divine kindness comes to light.”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“'ויקרא אברם שם וגו AND ABRAM CALLED THE NAME [OF HIS SON] etc. — Although Abram had not heard the words of the angel when he said to Hagar “and thou shalt call his name Ishmael”, yet the Holy Spirit rested upon him and he called him Ishmael.”

Post-Reformation

c. 1650 – 1900
1714
A.D.
Matthew Henry Reformed
1662–1714
“It is here taken for granted, though not expressly recorded, that Hagar did as the angel commanded her, returning to here mistress and submitting herself; and then, in the fulness of time, she brought forth her son. Note, Those who obey divine precepts shall have the comfort of divine promises. This was the son of the bond-woman that was born after the flesh (Gal 4:23), representing the unbelieving Jews, v. 25. Note, 1. Many who can call Abraham father are yet born after the flesh, Mat 3:9. 2. The carnal seed in the church are sooner brought forth than the spiritual. It is an easier thing to persuade men to assume the form of godliness than to submit to the power of godliness.”
Source
1771
A.D.
John Gill Reformed
1697–1771
“And Hagar bare Abram a son,.... Being returned to his house, and received by him, and reconciled to Sarai, she brought forth a son to Abram, according to the prediction of the angel: and Abram called his son's name, which Hagar bare, Ishmael; and this name Jarchi suggests he gave by the inspiration of the Holy Spirit that dwelt in him: but it is highly reasonable to suppose, that Hagar upon her return reported to Abram the whole of the conversation she had with the angel; wherefore Abram believing what she said, in obedience to the order and command of the angel, gave him this name.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“And Hagar bare Abram a son, etc. - It appears, therefore, that Hagar returned at the command of the angel, believing the promise that God had made to her. Called his son's name - Ishmael - Finding by the account of Hagar, that God had designed that he should be so called. "Ishmael," says Ainsworth, "is the first man in the world whose name was given him of God before he was born." In the preceding chapter we have a very detailed account of the covenant which God made with Abram, which stated that his seed would possess Canaan; and this promise, on the Divine authority, he steadfastly believed, and in simplicity of heart waited for its accomplishment. Sarai was not like minded. As she had no child herself, and was now getting old, she thought it necessary to secure the inheritance by such means as were in her power; she therefore, as we have seen, gave her slave to Abram, that she might have children by her. We do not find Abram remonstrating on the subject; and why is he blamed? God had not as yet told him how he was to have an heir; the promise simply stated, He that shall come forth out of thine own bowels shall be thine heir, Gen 15:4. Concubinage, under that dispensation, was perfectly lawful; therefore he could, with equal justice and innocence, when it was lawful in itself, and now urged by the express desire of Sarai, take Hagar to wife. And it is very likely that he might think that his posterity, whether by wife or concubine, as both were lawful, might be that intended by the promise. It is very difficult to believe that a promise which refers to some natural event can possibly be fulfilled but through some natural means. And yet, what is nature but an instrument in God's hands? What we call natural effects are all performed by supernatural agency; for nature, that is, the whole system of inanimate things, is as inert as any of the particles of matter of the aggregate of which it is composed, and can be a cause to no effect but as it is excited by a sovereign power. This is a doctrine of sound philosophy, and should be carefully considered by all, that men may see that without an overruling and universally energetic providence, no effect whatever can be brought about. But besides these general influences of God in nature, which are all exhibited by what men call general laws, he chooses often to act supernaturally, i.e., independently of or against these general laws, that we may see that there is a God who does not confine himself to one way of working, but with means, without means, and even against natural means, accomplishes the gracious purposes of his mercy in the behalf of man. Where God has promised let him be implicitly credited, because he cannot lie; and let not hasty nature intermeddle with his work. The omniscience of God is a subject on which we should often reflect, and we can never do it unfruitfully while we connect it, as we ever should, with infinite goodness and mercy. Every thing, person, and circumstance, is under its notice; and doth not the eye of God affect his heart? The poor slave, the stranger, the Egyptian, suffering under the severity of her hasty, unbelieving mistress, is seen by the all-wise and merciful God. He permits her to go to the desert, provides the spring to quench her thirst, and sends the Angel of the covenant to instruct and comfort her. How gracious is God! He permits us to get into distressing circumstances that he may give us effectual relief; and in such a way, too, that the excellence of the power may appear to be of him, and that we may learn to trust in him in all our distresses. God delights to do his creatures good. In all transactions between God and man, mentioned in the sacred writings, we see one uniform agency; the great Mediator in all, and through all; God ever coming to man by him, and man having access to God through him. This was, is, and ever will be the economy of grace. "The Father hath sent me: - and no man cometh unto the Father but by me." God forbid that he should have cause to complain of us, "Ye will not come unto me, that ye might have life."”
Source
1849
A.D.
1774–1849
“Agar being returned home, and having obtained pardon. — Ismael, as the angel had foretold; an honour shewn to very few; such as Isaac, Solomon, Jesus, &c. (Haydock) Bible Text & Cross-references: Abram marrieth Agar, who bringeth forth Ismael. 1 Now Sarai, the wife of Abram, had brought forth no children: having a handmaid, an Egyptian, named Agar, 2 She said to her husband: Behold, the Lord hath restrained me from bearing: go in unto my handmaid, it may be I may have children of her at least. And when he agreed to her request, 3 She took Agar the Egyptian her handmaid, *ten years after they first dwelt in the land of Chanaan, and gave her to her husband to wife. 4 And he went in to her. But she perceiving that she was with child, despised her mistress. 5 And Sarai said to Abram: Thou dost unjustly with me: I gave my handmaid into thy bosom, and she perceiving herself to be with child, despiseth me. The Lord judge between me and thee. 6 And Abram made answer, and said to her: Behold thy handmaid is in thy own hand, use her as it pleaseth thee. And when Sarai afflicted her, she ran away. 7 And the angel of the Lord having found her, by a fountain of water in the wilderness, which is in the way to Sur in the desert, 8 He said to her: Agar, handmaid of Sarai, whence comest thou? and whither goest thou? And she answered: I flee from the face of Sarai, my mistress. 9 And the angel of the Lord said to her: Return to thy mistress, and humble thyself under her hand. 10 And again he said: I will multiply thy seed exceedingly, and it shall not be numbered for multitude. 11 And again: Behold, said he, thou art with child, and thou shalt bring forth a son: and thou shalt call his name Ismael, because the Lord hath heard thy affliction. 12 He shall be a wild man: his hand will be against all men, and all men’s hands against him: and he shall pitch his tents over against all his brethren. 13 And she called the name of the Lord that spoke unto her: Thou the God who hast seen me. For she said: Verily, here have I seen the hinder parts of him that seeth me.* 14 Therefore she called that well, the well of him that liveth and seeth me. The same is between Cades and Barad. 15 And Agar brought forth a son to Abram: who called his name Ismael. 16 Abram was four score and six years old when Agar brought him forth Ismael.”
Source
1863
A.D.
1796–1863
“II. P. " Beerdahai-roi." Inflra 24 : 62. w II. P. " Abram called his son's name, which Hagar bare, Ishmael."”
1875
A.D.
Keil & Delitzsch Lutheran
1861–1875
“Having returned to Abram's house, Hagar bare him a son in his 86th year. He gave it the name Ishmael, and regarded it probably as the promised seed, until, thirteen years afterwards, the counsel of God was more clearly unfolded to him.”
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.