Which some professing have erred concerning the faith. Grace be with thee.
Which (falsely-called science) some professing ... erred (note, 1 Timothy 1:6) - literally, missed the mark (2 Timothy 3:7-8). True sagacity is inseparable from faith. 'It is incredible that any forger in the second century should have applied so mild an expression to followers of the Marcionite Gnosis' (Ellicott).
Grace - Greek, 'the grace,' namely, of God, for which we Christians look, and in which we stand (Alford.)
Be with thee. He restricts the salutation to Timothy, as the letter was not to be read in public (Bengel). So Delta f g, Vulgate. But 'Aleph (') A G g read 'be with you.'
Amen. So C. Omitted in 'Aleph (') A G Delta.