St. Matthew (8:1–4) records that Our Lord, descending from the Mount of Beatitudes after the Sermon on the Mount, was met by a leper. Leprosy in the Law of Moses (Lev 13–14) imposed total separation from the community: 'He shall dwell alone without the camp.' To approach Jesus was an act of supreme faith; to touch a leper, an act forbidden by the Law. Yet the Lord 'stretched forth his hand and touched him,' breaking through the wall of separation.
The healing was instantaneous: 'And forthwith his leprosy was cleansed.' Christ then instructed him to tell no one but to go and show himself to the priest and offer the sacrifices prescribed by Moses (Lev 14:2–32) — a sign that the Lord came not to abolish the Law but to fulfil it. The healing is also recorded by St. Mark (1:40–45) and St. Luke (5:12–16).
The Fathers saw in this miracle the touch of Christ that cleanses the soul from the leprosy of sin — a touch which no longer infects the One who touches, but heals the one who is touched.