en_tn_condensed/mrk/01/44.md

show yourself to the priest

Jesus told the man to show himself to the priest so that the priest could look at his skin to see if his leprosy was really gone. The law of Moses required people to present themselves to the priest if they had been unclean but were no longer unclean.

a testimony to them

Possible meanings are 1) "a testimony to the priests" or 2) "a testimony to the people."