Matthew 10:42

The "little ones" in view of the context probably refer to the persecuted disciples who remain faithful to the Lord. Anyone who assists one of them by giving him or her even a cup of refreshing cold water will receive a reward from God. That person can even give the cup of cold water in the name of a follower of Jesus, not in the name of Jesus Himself. The point is that no act of kindness for one of Jesus’ suffering disciples will pass without God’s reward.

"Keep in mind that the theme of this last section is discipleship, not sonship. We become the children of God through faith in Christ; we are disciples as we faithfully follow Him and obey His will. Sonship does not change, but discipleship does change as we walk with Christ. There is great need today for faithful disciples, believers who will learn from Christ and live for Him." [Note: Wiersbe, 1:40.]

This Mission Discourse (ch. 10) is instruction for Jesus’ disciples in view of their ministry to call people to prepare for the kingdom. Jesus gave the 12 Apostles specific direction about where they should go and to whom they should minister. However, He broadened His instruction in view of mounting opposition to give guidance to disciples who would succeed the Twelve. Their ministry was essentially the same as that of the apostles. Jesus did not reveal here that Israel’s rejection of Him would result in a long gap between His first and second advents. That gap is irrelevant to the instruction and its meaning. Christian disciples today need to do essentially what the Twelve were to do but to a different audience and region (Matthew 28:19-20). Jesus explained those changes after His firm rejection by the Jews.