'Strap' in the Bible

And he was preaching, saying, "One [who is] more powerful than I is coming after me, of whom I am not worthy to bend down [and] untie the strap of his sandals.

John answered them all, saying, "I baptize you with water, but the one who is more powerful than I [am] is coming, of whom I am not worthy to untie the strap of his sandals. He will baptize you with the Holy Spirit and fire.

the one who comes after me, of whom I am not worthy {to untie} the strap of his sandal!"