John Gill

For I perceive that thou art in the gall of bitterness,.... Alluding to Deu 29:18 with which compare Heb 12:15 and signifying, that he was in a state of nature and unregeneracy; under the power and dominion of covetousness, ambition, and hypocrisy; and in a way pernicious to himself, infectious to others, and ungrateful to God, and to good men; and that instead of the root of the matter, the truth of grace being in him, there was nothing in him but the bitter root of sin; which bore gall and wormwood, and everything that was nauseous and disagreeable: and in the bond of iniquity; referring to Pro 5:22 and suggesting, that he was held fast bound in the bonds of sin, and with the cords of iniquity, or was entirely under the government of his lusts: the preposition which we render "in", may retain here, as is by some observed, its proper sense of "for", or "into"; and have the same signification it has in Heb 1:5 "I will be to him for a father", or "a father", and "he shall be to me for a son", or "a son": and then the sense of Peter is, I plainly perceive and clearly see by thy words and actions, that thou art nothing else but a lump of bitter gall, and a bundle of sin and wickedness.