If a man be overtaken (εαν κα προλημφθη ανθρωπος). Condition of third class, first aorist passive subjunctive of προλαμβανω, old verb to take beforehand, to surprise, to detect.
Trespass (παραπτωματ). Literally, a falling aside, a slip or lapse in the papyri rather than a wilful sin. In Polybius and Diodorus. Koine word.
Ye which are spiritual (ο πνευματικο). See on 1. Corinthians 3:1. The spiritually led (Galatians 5:18), the spiritual experts in mending souls.
Restore (καταρτιζετε). Present active imperative of καταρτιζω, the very word used in Matthew 4:21 of mending nets, old word to make αρτιος, fit, to equip thoroughly.
Looking to thyself (σκοπων σεαυτον). Keeping an eye on as in 2. Corinthians 4:18 like a runner on the goal.
Lest thou also be tempted (μη κα συ πειρασθηις). Negative purpose with first aorist passive subjunctive. Spiritual experts (preachers in particular) need this caution. Satan loves a shining mark.