3. προσέχετε ἑαυτοῖς. The following lesson of forgiveness is added because the hard repellent spirit of aggressive Pharisaism and spiritual pride was of all others the most likely to cause offences. It broke up the bruised reed, and stamped on the smoking flax.
ἐὰν ἁμάρτῃ. ‘If he sin,’ omitting “against thee.” Comp. Mat 18:15-17; Mat 18:21-22.
ἐπιτίμησον … ἄφες. The former duty had been fully recognised in the old dispensation (Lev 19:17; Pro 17:10); the latter far more distinctly and emphatically in the new (Mat 18:15). The former is only intended as a help to the latter, 1Th 5:14.