Mark 1:7
And preached, saying, There comes one mightier than I after me, the lace of whose shoes I am not worthy to stoop down and unloose.
Nave's Topical Index—AKJV

Luke 3:16
John answered, saying to them all, I indeed baptize you with water; but one mightier than I comes, the lace of whose shoes I am not worthy to unloose: he shall baptize you with the Holy Ghost and with fire:
Nave's Topical Index—AKJV