Some translations set each line of poetry farther to the right than the rest of the text to make it easier to read. The ULB does this with the poetry in 1:2-3, which are words from the OT.
The Jews thought that people who had the skin disease called leprosy were unclean and so unable to properly worship God. When Jesus made people "clean," he healed their diseases and forgave their sins so they could worship God. (See: [[rc://en/tw/dict/bible/kt/unclean]] and [[rc://en/tw/dict/bible/kt/clean]])
No one knows for sure what Jesus meant when he said, "The kingdom of God is near." Some think he meant that the kingdom was present as he was speaking, and others think that the kingdom has still not come yet.