Mark 1:7 - Ellicott's Commentary On The Whole Bible

There cometh one mightier than I. — See Note on Matthew 3:11; but note the slight difference — not, as there, “whose shoes I am not worthy to bear,” but “the latchet of whose shoes I am not worthy to stoop down and unloose.” Latchet,” a word now obsolete, was the “thong” or “lace” with which shoes or sandals were fastened. To stoop down and loosen the sandals was commonly the act of the servant who afterwards carried them, but it expressed more vividly what we should call the menial character of the office, and therefore, we may believe, was chosen by St. Mark. (See Introduction.)