'Mightier' in the Bible

I indeed baptise you with water to repentance, but he that comes after me is mightier than I, whose sandals I am not fit to bear; he shall baptise you with the Holy Spirit and fire;

And he preached, saying, There comes he that is mightier than I after me, the thong of whose sandals I am not fit to stoop down and unloose.

John answered all, saying, I indeed baptise you with water, but the mightier than I is coming, the thong of whose sandals I am not fit to unloose; he shall baptise you with the Holy Spirit and fire;