From: Mark 1:40-45
The Curing of a Leper
 And a leper came to Him (Jesus), beseeching Him, and kneeling said to Him, "If You will, You can make me clean."  Moved with pity, He stretched out His hand and touched him, and said to him, "I will; be clean."  And immediately the leprosy left him, and he was made clean.  And He sternly charged him, and sent him away at once,  and said to him, "See that you say nothing to anyone; but go, show yourself to the priest, and offer for your cleansing what Moses commanded, for a proof to the people."  But he went out and began to talk freely about it, and spread the news, so that Jesus could no longer openly enter a town, but was out in the country; and people came to Him from every quarter.
40-44. Leprosy was seen as a punishment from God (cf. Numbers 12:10-15). The disappearance of the disease was regarded as one of the blessings of the messianic times (Isaiah 35:8; cf. Matthew 11:5; Luke 7:22). Because leprosy was contagious, the Law declared that lepers were impure and that they transmitted impurity to those who touched them and to places they entered. Therefore, they had to live apart (Numbers 5:2; 12:14ff) and to show that they were lepers by certain external signs. On the rite of purification, see the note on Matthew 8:4.
[The note on Matthew 8:4 states:
4. According to the Law of Moses (Leviticus 14), if a leper is cured of his disease, he should present himself to a priest, who will register the cure and give him a certificate which he needs to be reintegrated into the civil and religious life of Israel. Leviticus also prescribes the purifications and sacrifice he should offer. Jesus' instruction to the leper is, then, in keeping with the normal way of fulfilling what the laws laid down.]
The passage shows us the faithful and confident prayer of a man needing Jesus' help and begging Him for it, confident that, if Our Lord wishes, He can free him from the disease (cf. Matthew 8:2). "This man prostrated himself on the ground, as a sign of humility and shame, to teach each of us to be ashamed of the stains of his life. But shame should not prevent us from confessing: the leper showed his wound and begged for healing. If You will, he says, You can make me clean; that is, he recognized that the Lord had the power to cure him" (St. Bede, "In Marci Evangelium Expositio, in loc.").
On the discretion and prudence Jesus required regarding His person, see the note on Mark 1:34 and Matthew 9:30.
[The note on Mark 1:34 states:
34. Demons possess a supernatural type of knowledge and therefore they recognize Jesus as the Messiah (Mark 1:24). Through the people they possess they are able to publish this fact. But Our Lord, using His divine powers, orders them to be silent. On other occasions He also silences His disciples (Mark 8:30; 9:9), and He instructs people whom He has cured not to talk about their cure (Mark 1:4; 5:43; 7:36; 8:26). He may have acted in this way to educate the people away from a too human and political idea of the Messiah (Matthew 9:30). Therefore, He first awakens their interest by performing miracles and gradually, through His preaching, gives them a clearer understanding of the kind of Messiah He is.
Some Fathers of the Church point out that Jesus does not want to accept, in support of the truth, the testimony of him who is the father of lies.]
[The note on Matthew 9:30 states:
30. Why did our Lord not want them to publicize the miracle? Because His plan was to gradually manifest Himself as the Messiah, the Son of God. He did not want to anticipate events which would occur in their own good time; nor did He want the crowd to start hailing Him as Messiah King, because their notion of messiah was nationalistic, not a spiritual one. However, the crowd did in fact proclaim Him when he worked the miracles of the loaves and the fish (John 6:14-15): "When the people saw the sign which He had done, they said, `This is indeed the prophet who is to come into the world!' Perceiving then that they were about to come and take Him by force to make Him king, Jesus withdrew again to the hills by Himself."]
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.