Augustine of Hippo
Catena Aurea · Lukasevangelium 3
And as the people were in expectation, and all men mused in their hearts of John, whether he were the Christ, or not; John answered, saying unto them all, I indeed baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose: he shall baptize you with the Holy Ghost and with fire. Whose fan is in his hand, and he will throughly purge his floor, and will gather the wheat into his garner; but the chaff he will burn with fire unquenchable.
(de Cons. Evang. lib. ii. 12.) Matthew says, Whose shoes I am not worthy to bear. If therefore it is worth while to understand any difference in these expressions, we can only suppose that John said one at one time, another at another, or both together, To bear his shoes, and to loose the latchet of his shoes,so that though one Evangelist may have related this, the others that, yet all have related the truth. But if John intended no more when he spoke of the shoes of our Lord but His excellence and his own humility, whether he said loosing the latchet of the shoes, or bearing them, they have still kept the same sense who by the mention of shoes have in their own words expressed the same signification of humility.