The “kiss of death” was given to Jesus by one of His own disciples, the treacherous Judas. Since Jesus chose His twelve disciples, we can assume that Judas was, at first, a sincere follower.
But the Gospels make it clear that he was, or became, a bad character, thieving from the group’s common treasury, which he was in charge of (John 12:6). Judas went to the Jewish priests and offered to lead them to Jesus in a secluded spot, so they could arrest Him without fear of public reaction.
The priests gave him thirty pieces of silver. After the Last Supper, while Jesus prayed in the Garden of Gethsemane, Judas led the priests’ soldiers to Jesus and identified Him by kissing Him. Judas regretted his action, and he returned his “blood money” to the priests, then went and hanged himself.
In paintings of the Last Supper, Judas is usually portrayed holding a bag with his thirty pieces of silver. His name has passed into the language as meaning “traitor.”