William Burkitt on 1 Corinthians 16:13

Three duties are here exhorted to, namely, watchfulness, stedfastness in the faith, and holy fortitude and courage.

1. Watchfulness, a necessary and daily duty; we cannot be safe one moment without it; something we must watch over, something we must watch against all sin, all appearance of sin, all temptations to sin, all occasions of sinning; we must watch for all opportunities of glorifying God, all opportunities of doing good to others.

2. Stedfastness in the faith; perseverance in the faith of Christ, and stedfastness in his holy religion, is the great and indispensible duty of every Christian that has a due regard to his soul's salvation: Watch ye, stand fast in the faith:

3. Christian fortitude and holy courage: Quit yourselves like men, be strong. Where we have the Christian's spiritual enemies supposed and implied, sin, Satan, and the world; and his duty declared, and himself encouraged to play the man in opposing, or contending with, and striving against, them.

Verily, a Christian above all men needs courage and resolution; he can do nothing as a Christian, but it is an act of valour; it requires much more courage to be a Christian than to be a captain.

Alas! how many of the valiant sword-men of the world have showed themselves mere cowards, who have come out of the field with victory, and banners displayed; but after all lived and died slaves at home, slaves to their base lusts! It requires more prowess, more bravery and greatness of spirit, to conquer ourselves, than to command an army of men. Therefore quit ye like men, be strong.