John the Baptist said he was not worthy to stoop down and untie what?

Answer: The straps of His sandals

John said One more powerful was coming, whose sandal straps he was not worthy to stoop down and untie.

“And he proclaimed: “After me will come One more powerful than I, the straps of whose sandals I am not worthy to stoop down and untie.”— Mark 1:7 (BSB)