The interpretation timeline
Matthew 10:42 Douay-Rheims

And whosoever shall give to drink to one of these little ones a cup of cold water only in the name of a disciple, amen I say to you, he shall not lose his reward.

A.D. 367 – 1871 4 witnesses

Patristic

before A.D. 750
367
A.D.
Hilary of Poitiers Patristic
c. A.D. 310–367
“Or; Seeing beforehand that there would be many who would only glory in the name of Apostleship, but in their whole life and walk would be unworthy of it, He does not therefore deprive of its reward that service which might be rendered to them in belief of their religious life. For though they were the very least, that is, the greatest of sinners, yet even small offices of mercy shewn them, such as are denoted by the cup of cold water, should not be shewn in vain. For the honour is not done to a man that is a sinner, but to his title of disciple.”
Source
420
A.D.
Jerome Patristic
c. A.D. 347–420
“That none should say, I am poor and therefore cannot be hospitable, He takes away even this plea by the instance of a cup of cold water, given with good will. He says cold water, because in hot, poverty and lack of fuel might be pleaded. And whosoever shall give to drink to one of the least of these a cup of cold water only in the name of a disciple, verily I say unto you, he shall not lose his reward.”
Source

Scholastic

c. 1100 – 1500
1256
A.D.
Thomas Aquinas Catholic
1225–1274
“"And he who does not take up his cross." Thus it has been said, "he who loves father," etc.; nay, I say more: he who loves himself more than me is not worthy of me. For nothing can fill the whole affection except God. And therefore Deuteronomy 6:5: "You shall love the Lord your God with your whole heart, and with your whole soul, and with your whole strength." Hence he says, "he who does not take up his cross and follow me is not worthy of me." He means that whoever is not prepared even to suffer death for the sake of the truth, and that death most of all, namely the death of the cross, is not worthy of me; nay, he ought even to glory in the cross, as is found in Galatians, the last chapter, 14: "But far be it from me to glory, save in the cross of the Lord." And in this he foretells his own death, and the manner of his death; 1 Peter 2:21: "Christ suffered for us, leaving you an example, that you should follow his steps." Again, it is expounded otherwise: for he takes up the cross who afflicts the flesh, as is found in Galatians 5:24: "They who are Christ's have crucified their flesh with its vices and concupiscences," etc. Again, the cross is borne in the heart, when one is grieved for sin, as the Apostle said, 2 Corinthians 11:29: "Who is scandalized, and I am not on fire?" Again, this does not suffice, unless one follows the Lord. Hence also, "and follows me." If you fast, if you have compassion for your neighbor, but not for my sake, you are not worthy of me. For it is a great thing to follow the Lord, as is found in Ecclesiasticus 23:38: "It is a great glory to follow the Lord." But they might say, what shall we get from this? Therefore he shows the penalty of the disobedient; hence he says, "he who finds his soul shall lose it." Soul is taken for life. When someone is in danger of losing his money, he is accustomed to say, "I have lost my money"; and if he is freed from the danger, he says he has found his money. Similarly, if someone is in danger of the body, and is freed by some occasion, he says he has found his life. Whoever, therefore, finds his life, and has been in danger for my sake, and denies me in order to find his life, is not worthy of me. And "he who shall have lost his soul," that is, his life — that is, if he shall have exposed himself to death for my sake — "shall find it"; Proverbs 8:35: "He who shall find me, shall find life, and shall draw salvation from the Lord." "He who receives you, receives me." Here he sets down the remedy. You say that we should act thus. Whence shall we be able to live? Give us some indulgence. Just as the Pope gives to legates the power of granting indulgence, so the Lord gives a reward to those who receive them. And he sets down three things, of which two pertain to the lesser ones. He says therefore, "He who receives you, receives me" — because they will have God, since you are my members, since a member is of the member. Hence, "receives me." But they might say: you are poor; it is no great thing to receive a poor man, or even you. Nay, "he who receives me, receives him who sent me," because, as is found in John 5:23, "he who honors the Son, honors also my Father." It is a great thing to have God as a guest, as it was reckoned to Abraham for praise, as is found in Hebrews 13:2. Again, another thing will follow, namely the reward of a prophet. Hence, "he who receives a prophet in the name of a prophet, shall receive the reward of a prophet." There are two excellent things in a prophet. Namely, prophecy — Joel 2:28: "I will pour out my spirit upon all flesh, and your sons and your daughters shall prophesy"; likewise the gift of justice — 1 Corinthians 1:30: "But of him you are, who is made unto us wisdom and justice." "He who receives a prophet in the name of a prophet." It can be understood thus: he who receives a prophet in the name of a prophet, that is, because he is a prophet, shall receive the reward of a prophet. Or otherwise: you say that we should receive apostles; but there will come some false prophets, or false apostles. Therefore he says: I do not insist upon the truth, but upon the name. For whoever receives in the name of a prophet shall have a reward. And what reward? The same which you would have if you received a true prophet. Hence he says, "the reward of a prophet," that is, which he would have for a prophet. Again, it makes no difference who that one is, whether one or another. For he who receives a prophet receives the reward of a prophet, because the prophet is thereby made more ready to exercise his work; because not only those who do, receive a reward, but also those who consent to those who do, as is found in Romans 1, at the end. Hence, if you cooperate toward the good, from that good you receive a reward; if you minister the supports of life, you receive a reward; because otherwise he would not be able to fulfill his office. And the same holds for what follows: "he who receives a just man in the name of a just man, shall receive the reward of a just man." But someone might say: if Peter, or Elijah, were to come, I would gladly receive him; therefore he adds, "and whoever shall give a drink to one of these little ones," that is, of the faithful, as is found below in chapter 25:40: "Amen I say to you, as long as you did it to one of these my least brethren, you did it to me," etc.; as if to say: I care not whether they are great or small. Someone might say: I am poor, I have nothing to give; therefore he adds, "a cup of cold water": he does not say "of hot water," on account of the lack of wood, lest he be able to excuse himself thus; hence he means to say: whatever least thing one shall have done, he will have his reward. And he confirms this, saying, "Amen I say to you, he shall not lose his reward"; Isaiah 40:10: "Behold, the Lord shall come"; and it follows: "and his reward is with him, and his work before him."”
Source

Post-Reformation

c. 1650 – 1900
1871
A.D.
1871
“And whosoever shall give to drink unto one of these little ones--Beautiful epithet! Originally taken from Zac 13:7. The reference is to their lowliness in spirit, their littleness in the eyes of an undiscerning world, while high in Heaven's esteem. a cup of cold water only--meaning, the smallest service. in the name of a disciple--or, as it is in Mark (Mar 9:41), because ye are Christ's: from love to Me, and to him from his connection with Me. verily I say unto you, he shall in no wise lose his reward--There is here a descending climax--"a prophet," "a righteous man," "a little one"; signifying that however low we come down in our services to those that are Christ's, all that is done for His sake, and that bears the stamp of love to His blessed name, shall be divinely appreciated and owned and rewarded. Next: Matthew Chapter 11”
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.