Contradiction with Matthew 6:1-2
These verses caution against doing good deeds to be seen by others, whereas Matthew 10:42 seems to emphasize the virtue in giving even a small gift of cold water.
Matthew 6:1-2: Take heed that ye do not your alms before men, to be seen of them: otherwise ye have no reward of your Father which is in heaven. [alms: or, righteousness] [of your: or, with your]
Contradiction with Luke 18:22-23
Jesus instructs the rich young ruler to sell all he has and distribute to the poor for treasure in heaven, implying more significant sacrifice than Matthew 10:42, which speaks of a simple act of kindness.
Luke 18:22-23: Now when Jesus heard these things, he said unto him, Yet lackest thou one thing: sell all that thou hast, and distribute unto the poor, and thou shalt have treasure in heaven: and come, follow me.
Contradiction with James 2:14-17
These verses stress the importance of faith being accompanied by action, which might seem to contradict the idea that even a small act such as giving water is significant on its own.
James 2:14-17: What [doth it] profit, my brethren, though a man say he hath faith, and have not works? can faith save him?
Contradiction with Matthew 23:23
Jesus criticizes the Pharisees for neglecting weightier matters of the law, implying that minor acts like tithing spices are insufficient, contrasting with the positive light of a small act in Matthew 10:42.
Matthew 23:23: Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier [matters] of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone. [anise: Gr. dill]
Contradiction with Isaiah 64:6
This verse suggests that acts of righteousness can be unclean without God's grace, questioning the merit of any simple act such as in Matthew 10:42 as inherently righteous.
Isaiah 64:6: But we are all as an unclean [thing], and all our righteousnesses [are] as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.