Mr 1:7

Mr 1:7 And preached, saying, There cometh one mightier than I after me, the latchet of whose shoes I am not worthy to stoop down and unloose.

John references the verses that follow Mal 3:1 in describing the one who follows him. He doesn't quote the verses but restates their meaning:

Mal 3:2 But who may abide the day of his coming? and who shall stand when he appeareth? for he [is] like a refiner’s fire, and like fullers’ soap:

Mal 3:3 And he shall sit [as] a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the LORD an offering in righteousness.