Matthew 8:1-4 and Luke 17:11-19 both tell about how Jesus healed lepers. In Matthew 8, a man with leprosy asked Jesus to heal him, and Jesus granted the request. Jesus told the man not to mention the healing to anyone other than the priest.
In Luke 17, 10 men called out to Jesus from a distance, asking him to heal them. Jesus told them to visit the priest, and they found themselves healed as they went. While Jesus did not touch the 10 lepers but healed with his words, in the Matthew passage, Jesus touched the leper to heal him, which was against Hebraic law, as lepers were considered unclean.