The interpretation timeline
Luke 17:3 Douay-Rheims

Take heed to yourselves. If thy brother sin against thee, reprove him: and if he do penance, forgive him.

A.D. 397 – 1871 6 witnesses 9 excerpts

Patristic

before A.D. 750
397
A.D.
Ambrose of Milan Patristic
A.D. 339–397
“After the parable of the rich man who is tormented in punishment, Christ added a commandment to give forgiveness to those who turn themselves from their trespasses, lest any one through despair should not be reclaimed from his fault; and hence it is said, Take heed to yourselves.”
“That there might neither be hard-wrung pardon, nor a too easy forgiveness, neither a harsh upbraiding, to dishearten, nor an overlooking of faults, to invite to sin; therefore it is said in another place, Tell him his fault between him and thee alone. (Mat. 18:15.) For better is a friendly correction, than a quarrelsome accusation. The one strikes shame into a man, the other moves his indignation. He who is admonished will more likely be saved, because he fears to be destroyed. For it is well that he who is corrected should believe you to be rather his friend than his enemy. For we more readily give ear to counsel than yield to injury. Fear is a weak preserver of consistency, but shame is an excellent master of duty. For he who fears is restrained, not amended. But He has well said, If he trespass against thee. For it is not the same thing to sin against God and to sin against man.”
Source
“Or this number is used because God rested on the seventh day from His works. After the seventh day of the world everlasting rest is promised us, that as the evil works of that world shall then cease, so also may the sharpness of punishment be abated.”
735
A.D.
Bede the Venerable Patristic
c. A.D. 672–735
“But we must mark, that He does not bid us forgive every one who sins, but him only who repents of his sins. For by taking this course we may avoid offences, hurting no one, correcting the sinner with a righteous zeal, extending the bowels of mercy to the penitent.”
“By using the number seven He assigns no bound to the giving of pardon, but commands us either to forgive all sins, or always to forgive the penitent. For by seven the whole of any thing or time is frequently represented.”

Scholastic

c. 1100 – 1500
1107
A.D.
c. 1055–1107
“As if He says, Offences must needs come; but it does not follow that you must perish, if only you be on your guard: as it need not that the sheep should perish when the wolf comes, if the shepherd is watching. And since there are great varieties of offenders, (for some are incurable, some are curable,) He therefore adds, If thy brother trespass against thee, rebuke him.”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“And if he trespass against thee seven times in a day,.... For good men are frequently apt to fall into sin, and offend both God and man; see Pro 24:16 "and seven times in a day turn again to thee, saying, I repent"; as often as he sins, and appears to be truly sensible of it, and humble for it, and makes acknowledgments of it; and not only barely in words professes his concern for it, but there is reason to believe that he is heartily grieved for it, and to hope that he will behave better for the future: thou shalt forgive him; this seems to be occasioned by Peter's putting such a question to Christ, how often a brother might sin against him, and he forgive him; see Mat 18:21. The Jews plead for great tenderness and readiness to forgive penitents, when they ask for forgiveness; which they insist upon should be done: they say (q), "it is forbidden an injured person to be cruel, and not forgive; this is not the way of the seed of Israel: but when he that has done the injury asks of him, and prays him once and again, and he knows that he has returned from his sin, and hath repented of his evil, he ought to forgive him; and whoever makes haste to forgive, is praiseworthy.'' But then, they say (r), "if he brings all the rams of Nebaioth that are in the world, he is not to have pardon, unless he asks it of him.'' And they seem also to have set times for it, as well as restrain the frequent repetition of it: they observe (s); "if a man returns by repentance, in the intermediate time, (i.e. as the gloss explains it, between the beginning of the year, or New Year's Day, and the day of atonement,) they pardon him; but if he does not return in the intermediate time, though he brings all the rams of Nebaioth in the world, they do not pardon him.'' A man that was always forgiving, was reckoned by them an extraordinary man: it is said (t) of Mar Zutra bar Nachman, that he was , "forgiving every day"; but yet they do not seem to care to carry it to so great a length, and to repeat it so often as our Lord directs; they allow a man to forgive three times, but not a fourth; See Gill on Mat 18:22. (q) Maimon. Hilchot Chobel Umezik, c. 5. sect. 10. (r) T. Bab. Bava Kama, fol. 92. 1. (s) T. Bab. Rosh Hashama, fol. 17. 2. (t) Juchasin, fol. 90. 2.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“If thy brother trespass - See the notes on Mat 18:21, Mat 18:22.”
1871
A.D.
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.