Jamieson, Fausset & Brown

From which--namely, from a pure heart, good conscience, and faith unfeigned, the well-spring of love. having swerved--literally, "having missed the mark (the 'end') to be aimed at." It is translated, "erred," Ti1 6:21; Ti2 2:18. Instead of aiming at and attaining the graces above named, they "have turned aside (Ti1 5:15; Ti2 4:4; Heb 12:13) unto vain jangling"; literally, "vain talk," about the law and genealogies of angels (Ti1 1:7; Tit 3:9; Tit 1:10); Ti1 6:20, "vain babblings and oppositions." It is the greatest vanity when divine things are not truthfully discussed (Rom 1:21) [BENGEL].