2 Kings 17:15

And they rejected his statutes, and his covenant that he made
with their fathers
At Sinai and Horeb, see ( Exodus 24:8 ) ( Deuteronomy 29:1 ) ,

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 ) ( 30:19 ) ( 32:1 ) , 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

and became vain;
as sottish and stupid as the idols they worshipped; which is the usual fruit and effect of idolatry, see ( Romans 1:21-28 )

and went after the heathen that were round about them:
imitated them in their idolatrous practices, as the Moabites, Ammonites, Edomites concerning

whom the Lord had charged them, that they should not do like them;
of this charge see ( Deuteronomy 6:13 Deuteronomy 6:14 ) .