Fight the good fight of faith. Lay hold of the eternal life to which you were called, and you confessed the good confession in the sight of many witnesses.
Whereunto thou wast also called ... All men are called in the sense of being objects of God's invitation to receive eternal life; but, as so frequently in the New Testament, "a call" means one answered and responded to; and so it was with Timothy.  The time of his conversion is clearly in mind here, as the immediate reference to "the good confession" proves.