Matthew Poole and continuators on 2 Samuel 15:34

34 But if thou return to the City, and say unto Absalom, I will be thy servant, O king: as I have been thy fathers servant hitherto, so will I now also be thy servant: then mayest thou for me defeat the counsel of Ahithophel.

i. e. As faithful to thee▪ as I have been to thy Father; which he neither was, nor ought to be. And therefore, the profession of this was great dissimulation: and David's suggesting this crafty Counsel, may be reckon'd amongst his Errors: which, proceeding from a violent Temptation, and his present and pressing Straits, God was pleased mercifully to Pardon, and to direct this Evil Advice to a Good End.

Marginal references: Or, heretofore.