Albert Barnes Commentary 1 Corinthians 16:13

"Watch ye, stand fast in the faith, quit you like men, be strong." — 1 Corinthians 16:13 (ASV)

Watch ye. The exhortation in this and the following verse is evidently given in view of the peculiar dangers and temptations that surrounded them. The word used here (grhgoreite) means to keep awake, to be vigilant, and so on. This may perhaps be a military metaphor derived from the duty of those who are stationed as sentinels to guard a camp or to observe the movements of an enemy. The term is frequently used in the New Testament, and this duty is frequently enjoined (Matthew 24:41–42; Matthew 25:13; Mark 13:35; Luke 21:36; Acts 20:31; 1 Thessalonians 5:6; 2 Timothy 4:5).

The meaning here is that they were to watch, or be vigilant, against all the evils about which he had admonished them—the evils of dissension, of erroneous doctrines, of disorder, of false teachers, and so on. They were to watch, lest their souls be ruined and their salvation endangered; lest the enemies of truth and holiness steal silently upon them and surprise them. They were to watch with the same vigilance required of a sentinel guarding a camp, lest an enemy should come suddenly upon them and surprise the camp when the army was locked in sleep.

Stand fast in the faith. Be firm in holding and defending the truths of the gospel. Do not yield to any foe, but maintain the truth, and adhere to your confidence in God and to the doctrines of the gospel with unwavering constancy. (See Barnes on 1 Corinthians 15:1).

Be firm in maintaining what you believe to be true, and in holding on to your personal confidence in God, notwithstanding all the arts, insinuations, and teachings of seducers and the friends of false doctrine.

Quit you like men. andrizesye (from anhr, a man). The word occurs nowhere else in the New Testament. In the Septuagint it occurs in Joshua 1:6, 7, 9, 18; 1 Chronicles 28:20; 2 Chronicles 32:7; Nehemiah 2:1; and in eighteen other places. (See Trommius' Concordance.) It also occurs in classical authors. (See Xenophon, Oeconomicus 5.4.) It means to make someone manly or brave, or to show oneself a man; that is, not to be a coward, timid, or alarmed by enemies, but to be bold and brave. We have a similar phrase in common use: “Be a man,” or “Show yourself a man”; that is, do not be petty or cowardly.

Be strong. Be firm, fixed, steadfast. (Compare Ephesians 6:10: Be strong in the Lord, and in the power of his might.)