Matthew 10:8 Heal the sick, raise the dead, cleanse lepers, cast out demons. Freely you have received, freely you must give.
When the prophet Elisha healed Naaman the King of Syria of his leprosy by telling him to wash himself in the Jordan seven times, Naaman returned and tried to give him a gift. The prophet responded “As the LORD liveth, before whom I stand, I will receive none.” All Elisha did was pass the instructions which God gave him on to Naaman. Elisha received them freely, and therefore could not take anything for them in return.
Matthew 10:41 He receiving a prophet in the name of a prophet gains reward of the prophet, and he receiving a righteous man in the name of a righteous man gains reward of the righteous man.
In 1 Kings chapter 17, the widow of Zarephath received and sustained the prophet Elijah, and she was rewarded with sustenance in return, for the grain and oil did not fail in a time of famine. Then her son fell ill, but she also received the life of her son, even though it was at first through trial. In 2 Kings chapter 4 the woman who made a place of rest for the prophet Elisha, not knowing for certain but only perceiving that he was a man of God, was also rewarded by conceiving a son although she had been barren. That child too, nearly died, and was delivered through his mother's abidance in the faith. Here we have those same promises if we continue to exhibit that same faith. Yet there is a common theme here, for we see that in each instance a single act of kindness was not sufficient: rather we must continue in faith without failure.