Therefore, having put away falsehood, let each one of you speak the truth with his neighbor, for we are members one of another.
25. Wherefore, putting away lying. From this head of doctrine, that is, from the righteousness of the new man, all godly exhortations flow, like streams from a fountain; for if all the precepts which relate to life were collected, yet, without this principle, they would be of little value.
The apostle having gone through his exhortation to mutual love, unity, and concord, in the foregoing verses, there follows in these an exhortation to Christian purity and holiness of heart and life, and that both more general (Eph 4:17-24) and in several particular instances, Eph 4:25-32.
Commenting on Ephesians 4:17-32
Neither give place to the devil. Or "to the accuser", or "slanderer"; that is, to any adversary, that takes delight in slandering and reproaching the saints; give such no room, nor reason, to calumniate the doctrine and ways of Christ, through an unbecoming conversation, by lying and sinful anger, or by other means; or rather the devil, the great accuser of the brethren is meant...