Jamieson, Fausset and Brown on 1 Timothy 1:6

6. 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," 1Ti 6:21; 2Ti 2:18. Instead of aiming at and attaining the graces above named, they "have turned aside (1Ti 5:15; 2Ti 4:4; He 12:13) unto vain jangling"; literally, "vain talk," about the law and genealogies of angels (1Ti 1:7; Tit 3:9; 1:10); 1Ti 6:20, "vain babblings and oppositions." It is the greatest vanity when divine things are not truthfully discussed (Ro 1:21) [Bengel].