And they rejected his statutes, and his covenant that he made with their fathers, and his testimonies which he testified against them; and they followed vanity, and became vain, and went after the heathen that were round about them, concerning whom the LORD had charged them, that they should not do like them.

And they rejected his statutes, and his covenant that he made with their fathers, and his testimonies which he testified unto them; and they followed vanity, and became vain, and went after the nations that were round about them, concerning whom Jehovah had charged them that they should not do like them.

And they rejected his ordinances and the covenant that he made with their fathers, and the testimonies which he testified against them: and they followed vanities, and acted vainly: and they followed the nations that were round about them, concerning which the Lord had commanded them that they should not do as they did.

and reject His statutes and His covenant that He made with their fathers, and His testimonies that He testified against them, and go after the vain thing, and become vain, and after the nations that are round about them, of whom Jehovah commanded them not to do like them;

And they went against his rules, and the agreement which he made with their fathers, and his laws which he gave them; they gave themselves up to things without sense or value, and became foolish like the nations round them, of whom the Lord had said, Do not as they do.

and they rejected His statutes, and His covenant that He made with their fathers, and His testimonies wherewith He testified against them; and they went after things of nought, and became nought, and after the nations that were round about them, concerning whom the LORD had charged them that they should not do like them;

They rejected his statutes, and his covenant that he made with their fathers, and his testimonies which he testified to them; and they followed vanity, and became vain, and followed the nations that were around them, concerning whom the LORD had commanded them that they should not do like them.

And they cast aside his ordinances, and the covenant that he formed with their fathers, and the testimonies which he testified to them. And they pursued vanities and acted vainly. And they followed the nations that were all around them, concerning the things which the Lord had commanded them not to do, and which they did.

As idols are "vanity" and "nothingness," mere weakness and impotence, so idolators are "vain" and impotent. Their energies have been wasted, their time misspent; they have missed the real object of their existence; their whole life has been a mistake; and the result is utter powerlessness. Literally, the word rendered "vanity" seems to mean "breath" or "vapor" - a familiar image for nonentity. It occurs frequently in the prophets, and especially in Jeremiah (e. g. Jeremiah 2:5; Jeremiah 8:19; Jeremiah 14:22, etc.).

And they rejected his statutes, and his covenant that he made with their fathers,.... At Sinai and Horeb, see Exodus 24:8,
and his testimonies which he testified against them; calling heaven and earth to witness what he would do to them if they broke his laws, Deuteronomy 4:26, and which were so many testifications of his mind and will what they should do, or otherwise what should be done to them; Ben Gersom also interprets this of the feasts of the passover and tabernacles, which were witnesses of Israel's coming out of Egypt, and of the sanctification and redemption of the firstborn, a testimony of the slaying the firstborn in Egypt:
and they followed vanity; idols, which are vain things for help, can neither hear, see, speak, &c.
and became vain; as sottish and stupid as the idols they worshipped; which is the usual fruit and effect of idolatry, see Romans 1:21.
and went after the heathen that were round about them: imitated them in their idolatrous practices, as the Moabites, Ammonites, Edomites, &c. concerning
whom the Lord had charged them, that they should not do like them; of this charge see Deuteronomy 6:13.

"They followed vanity and became vain:" verbatim as in Jeremiah 2:5.
A description of the worthlessness of their whole life and aim with regard to the most important thing, namely, their relation to God. Whatever man sets before him as the object of his life apart from God is הבל (cf. Deuteronomy 32:21) and idolatry, and leads to worthlessness, to spiritual and moral corruption (Romans 1:21). "And (walked) after the nations who surrounded them," i.e., the heathen living near them. The concluding words of the verse have the ring of Leviticus 18:3.

Vanity - Idols; so called because of their nothingness, impotency, and unprofitableness; and by the long worship of idols, they were made like them, vain, sottish, and senseless creatures.