And a leper came to him, imploring 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 Jesus 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 them." 
But he went out and began to talk freely about it, and to spread the news, so that Jesus could no longer openly enter a town, but was out in desolate places, and people were coming to him from every quarter. 
--Mark 1:40-45

In this account, Jesus Christ heals a leper. Leprosy was a common affliction, and though the Gospels record only 2 events where Jesus healed leprosy (the other being Luke 17, where He healed 10 lepers), I imagine He healed many that were not recorded for us in the Bible.

“Leprosy” was a catch-all term for various skin afflictions. This man has what today would be called Hansen’s Disease. This terrible disease is caused by micro-bacteria that attack the nerves and anesthetize the skin. Without the sensation of touch, the victim would be prone to injury. The disease would go anywhere between 10-30 years, and the afflicted usually died from other diseases because they had no resistance.

The disease was also fairly communicable. Therefore in Jesus’ day, lepers were not allowed in mainstream society. The only people they could be around were… other lepers. You couldn’t be home, you couldn’t go to the Temple or synagogue, you couldn’t punch in at work; almost as terrible as the disease itself was the isolation it brought from a “normal” life. In fact, according to the Mosaic Law, lepers had to tatter their clothes so they would be easily recognized, as well as cry out “UNCLEAN” when they were in the vicinity of others. (Leviticus 13)

So this leper comes to Jesus (note: lepers were never allowed to approach people like this!). And the parallel account in Luke 5:12 says this man was full of leprosy. He wasn’t a recent diagnosis; he was advanced stages. He came with an attitude of reverence and met the Savior who had an attitude of compassion. One touch from Jesus took the man from Stage 4 to complete health!

Jesus sent the man off with 2 commands: 1) Say nothing to anyone. 2) Show yourself to the priest. What’s with the commands? Well, Jesus said why the man needed to show himself to the priest: for a proof to them. Show the priest that Jesus Christ is the anointed Messiah, verified by Divine miracles. But why keep mum about this to everyone else? Jesus didn’t say why. But He gave this command a lot, apparently (see Mark 3:12, 5:43, 7:36, 8:25).

To borrow a term from the 2nd grade, the man must have thought it was Opposite Day. He did exactly what Jesus told him not to do. And I think we see in the last verse why Jesus told him not to say anything. The news spread to the point that Jesus was getting mobbed when He went near a city. So popular was this miracle worker that He couldn’t even walk down Main Street because people were coming after Him from everywhere.

The man serves as a positive and a negative example, leaving us with 2 big lessons…

1) Where the leper had a big win: When you ask God for something, remember that HIS will for you is always more important than YOUR will for you. Because He is God and you are… not. The leper (now “ex-leper“) knew Jesus had the power to heal him, but he didn’t know if Jesus willed to do it. "If you will, you can make me clean."The man didn’t lay any claims, He didn‘t tell Jesus what He had to do - he just yielded to God’s will. Yes, pray. Yes, pray specifically. Yes, pray expectantly. Don’t pray presumptuously. Your prayers should ultimately be asking God only for the things that He would want for you. God knows what is best for you; you only think you know what is best for you. So you always want to go with God’s verdict on the matter. This is praying according to God’s will. I am willing to bet 1John 5:14 became this man’s “life verse”.

2) Where the leper failed: When God tells you to do something, just do it. You don’t need to know why.Sometimes God’s instruction doesn’t make sense to us. It doesn’t have to. Even if we haven’t reasoned out the why of a command from God’s Word, we should do what He commands anyways. It’s simple obedience. God doesn’t call us to figure Him out, He calls us to trust Him.

p.s. - Wonders if Simon the Leper, deep down, wished that nickname didn‘t stick