John Calvin Commentary 2 Timothy 2:7

"Consider what I say; for the Lord shall give thee understanding in all things." — 2 Timothy 2:7 (ASV)

Understand what I say. He added this, not because of the obscurity of the comparisons he has set forth, but so that Timothy himself might ponder, how much more excellent is the warfare under the direction of Christ, and how much more abundant the reward; for, when we have studied it incessantly, we scarcely arrive at a full knowledge of it.

The Lord give thee understanding in all things. The prayer, which now follows, is added by way of correction. Because our minds do not easily rise to that incorruptible crown (1 Corinthians 9:25) of the life to come, Paul turns to God, to give understanding to Timothy. And hence we infer, that we are taught in vain no less, if the Lord does not open our understanding, than the commandments would be given in vain, if he did not impart strength to perform them. For who could have taught better than Paul? And yet, in order that he may teach effectively, he prays that God may instruct his disciple.