Matthew 10:42 continues the theme of Matthew 10:41 by stressing how even a seemingly insignificant gesture (Matthew 25:40; Mark 9:41) such as a cup of cold water given to only one of God’s disciples, is so highly regarded by God that it will most certainly be rewarded. While the reward is not specifically identified in Matthew 10:42, it is implied by the reward mentioned in Matthew 10:41, because the Master who rewards the disciple is God’s Servant (Matthew 10:40), who will reward his fellow servants.
Yes, Matthew 10:42 continues the theme of Matthew 10:41 by highlighting that even a gesture that is insignificant by worldly standards (Matthew 25:40; Mark 9:41) such as a cup of cold water given to only one of God’s disciples, is so highly regarded by God that it will most certainly be rewarded.1
Various exegetes have argued that the reward mentioned here is not specifically identified. However, in Matthew 10:42 it is indeed indirectly identified, for it is the reward of a disciple by means of an analogy to Matthew 10:41. The Master, who rewards the disciple, is God’s Servant (Matthew 10:40). In other words, Jesus as the crucified Son of God guarantees that God will reward everyone who honours and helps his humble disciples.2
From the preceding two verses it can be safely be deduced that the reward spoken of here stands in direct relation to the exhibition of brotherly love. In this verse one can indeed speak of even a small deed that is greatly rewarded.3
42 And whoever gives one of these little ones even a cup of cold water because he is a disciple, truly, I say to you, he will by no means lose his reward.”