Mark’s story of the healing of the leper is short but rich, involving many Markan motifs. It presents the height of Jesus’s rock star status and hints at conflict to come while revealing more of Jesus’s identity.
The leper models insider behavior: he comes into Jesus’s presence with firm faith that Jesus can heal him of his leprosy (1:40). Mark then reveals something about Jesus: he can be moved, and emotionally at that: “Moved with pity, he . . . said to him, ‘I will; be clean’” (1:41).
Mark, above all other evangelists, presents a dynamic Jesus, powerful beyond measure, but also emotional and vulnerable. Not only is he fully God and man, but he also displays a full range of passions and emotions to a degree unusual not only in the Gospels but, indeed, in all ancient literature. He is exhausted (katheudōn) in the boat in Mark 4:38, dead tired like the little dead girl in 5:39 (katheudei). He’s not in control of his healing powers in 5:28–30 when the hemorrhaging woman gets zapped by touching the hem of his garment. Jesus finds the lack of faith he encounters in his hometown of Nazareth disturbing in 6:6. Jesus is disappointed in 8:12, groaning or sighing deeply (anastenazō) at those Pharisees who seek signs. He is indignant in 10:14 when the disciples hinder the little children from coming to him. Jesus displays rank passion and anger in the cleansing of the Temple in 11:15–17. He declares he is ignorant of the time of the End in 13:32. Jesus is overwhelmed with sorrow in Gethsemane (14:34). And Jesus’s death in 15:33–39 portrays a pitiful, pathetic, vulnerable figure whose death in Mark’s Gospel is far from the triumphal image portrayed by John.
And so, moved with pity, Jesus cleanses the leper. This is more than a mild rash. Biblical leprosy included several different diseases, some of which, like Hansen’s disease, were disfiguring and even deadly. The leper’s healing isn’t cosmetic. As he did with Peter’s mother-in-law, Jesus here saves someone from creeping death. And like the hemorrhaging woman, who has menstrual impurity, and Jairus’s daughter, the little dead girl, who has corpse impurity, the leper is an outsider. Leviticus 13:45–46 commands lepers to keep their garments torn and heads bare, to live outside the camp, and to cry out “unclean, unclean” should they encounter anyone. Levitical law thus excluded lepers from Temple and synagogue rites and, moreover, effectively cut them off from social contact.
Mark’s Jesus restores such outsiders to full fellowship with Israel’s God not only by healing them of that which excludes them from worship but also by later declaring all foods clean (7:19). Certainly, restoration to the social sphere is important, but the major point isn’t simple inclusion for the sake of tolerance or diversity, a very modern/postmodern read of Jesus’s mission, but restoration to liturgical worship of Almighty God (which is why Jesus the Jew has the leper go to the priest in 1:44), through the person of Jesus himself, on his powerful authority.
Jesus here remains Jewish, committed to restoring creation to God and the sick and sinners to Israel. Hence, he’s quite happy to have the leper return to the Temple and synagogue and, so, commands him to offer what Moses commanded for the cleansing of leprosy. As in Matthew and Luke, the break comes later, when Jewish resistance to the Jew Jesus leads him to form a remnant community within Israel, which will later include Gentiles.
Why does Jesus command the leper to secrecy? First, although Jesus has healed many, many people, in sending the leper to the priest, there’s a new element of risk involved: the healing may arouse unhelpful messianic expectation. Jesus has come to save his people by dying for them as a new Isaac (see Mark 1:11), not by killing for them, which is what most Jews expected the Christ to do.
Second, it sets up the irony at the end of the story, when the women are commanded to speak and remain silent. The leper here is commanded to remain silent but speaks, and Mark describes his speaking in evangelical terms: he began to “preach” (kērussō) and spread “the word” (ton logon, 1:45). Third, the leper’s disobedience might make him miss Jesus’s true identity: the sacrifice for cleansing from leprosy in Leviticus 14:3–7 involves taking two birds, slaughtering one, smearing its blood on the other, and setting that other free, much like Jesus’s blood sets free those who participate in his Body and Blood, his Eucharist (14:22–25). Obedience leads to understanding, and understanding involves knowing Jesus’s true identity and mission.
Thanks to the leper’s preaching, Jesus’s popularity soars, and even when he hides in the country, people come to him from everywhere (1:45). The first chapter, then, presents Jesus Christ Superstar. But in what follows, Jesus’s popularity will sour.
 Acts follows the same pattern: Jewish resistance to the early Church, which was exclusively Jewish in Acts 1–7, leads to the inclusion of Gentiles (Acts 8 and 10 and following).