This I say therefore, and testify in the Lord, that ye henceforth walk not as other Gentiles walk, in the vanity of their mind, Walk not as other Gentiles walk - Ye are called to holiness by the Gospel, the other Gentiles have no such calling; walk not as they walk. In this and the two following verses the apostle gives a most awful account of the conduct of the heathens who were without the knowledge of the true God. I shall note the particulars.
1. They walked in the vanity of their mind, εν ματαιοτητι του νοος αὑτων· In the foolishness of their mind; want of genuine wisdom is that to which the apostle refers, and it was through this that the Gentiles became addicted to every species of idolatry; and they fondly imagined that they could obtain help from gods which were the work of their own hands! Here their foolishness was manifested.