Lucas 5:13

By stretching out His hand and touching the leper, Jesus was doing the unthinkable (Leviticus 13). He probably did this to express His compassion for the man as well as to identify Himself beyond doubt as the source of his healing (cf. Exodus 4:4; Exodus 6:6; Exodus 14:16; Exodus 15:12; Jeremiah 17:5; Acts 4:30). Jesus’ words offered him reassurance (cf. Luke 5:10). Jesus’ authority extended to power over disease and ceremonial uncleanness. Doctor Luke again noted an immediate cure (cf. Luke 4:35; Luke 4:39).

"The most significant lesson from the cleansing of the leper story is that even outsiders can experience God’s healing grace." [Note: Bock, Luke, p. 165.]