John tells them "After me will come one more powerful than I, the thongs of whose sandals I am not worthy to stoop down and untie. I baptize you with water, but he will baptize you with the Holy Spirit". Untying someone's sandals was a task commonly done by someone's slave. What baptising with the Holy Spirit refers to, as Jesus never baptises in Mark, is uncertain if one only considers Mark. has Jesus' disciples (but not Jesus) baptising at the same time as John the Baptist. (See also Paraclete, , , , ). and specify baptism with holy spirit "and fire".