They will represent Jesus so thoroughly that any who receives an apostle will be receiving both Jesus and the one who sent Him. Such people will share in the rewards to be given to the apostles.
Now Jesus describes part of what it means to receive one of His disciples, whom He calls “little ones.” Those who gives them a cup of cold water, because he is a disciple of Jesus, will not lose his or her reward of being included in the kingdom of heaven.
The implication is that those who serve Jesus disciples because they believe in Jesus and want to help the mission succeed will be rewarded.
In Jesus time, people preferred to drink cold water. A cup of cold water, if available, was not expensive. Even a very poor person could help the mission of Jesus by offering His workers some cold water along the way.
Wealth and status are no barrier to serving Jesus’ mission by giving assistance to His laborers, i.e. pastors, evangelist, teachers and preachers of God’s word.
If you have very little, think small. Do you have two slices of bread? Find someone who has none and share one. If you have no resources, find information that leads a friend to food and additional help. When you are suffering in poverty, no help is too small. Jesus told us that even a cup of clean water is worth giving (Matthew 10:42).