Expositor's Bible Commentary Commentary Ephesians 4:17

"This I say therefore, and testify in the Lord, that ye no longer walk as the Gentiles also walk, in the vanity of their mind," — Ephesians 4:17 (ASV)

“So” resumes the exhortation in v.3. In a solemn declaration the apostle strongly implores the Ephesians to abandon all their former practices, because both he and they are “in the Lord.” In other letters Paul has not been slow to remind Hebrew Christians that they must not cling to Jewish legal practices. In similar vein he now urges Gentiles not to fall back into their old self-indulgent habits. Such permissive behavior springs from an aimless and futile attitude to life that cuts the nerve of moral endeavor.