Jamieson, Fausset and Brown on 2 Timothy 2:5

5. And--"Moreover."

strive for masteries--"strive in the games" [Alford]; namely, the great national games of Greece.

yet is he not crowned, except--even though he gain the victory.

strive lawfully--observing all the conditions of both the contest (keeping within the bounds of the course and stript of his clothes) and the preparation for it, namely, as to self-denying diet, anointing, exercise, self-restraint, chastity, decorum, &c. (1Co 9:24-27).