The Treacherous Nature of Their Behaviour Is Described (Deuteronomy 32:15-18).
‘But Jeshurun waxed fat, and kicked,
You are waxed fat, you are grown thick, you are become sleek,
Then he forsook God who made him,
And lightly esteemed the Rock of his salvation.
They moved him to jealousy with what was strange,
With abominations they provoked him to anger.'
But His ‘righteous one' (Jeshurun) grew fat, and kicked out, they got fatter and fatter and grew sleek and well groomed and untrustworthy. Thus they forgot the One to Whom they owed it all. They ceased to be His righteous one. They forsook the God Who made them, they esteemed lightly the Rock on Whom their deliverance was built, the Rock which was their security. They made Him jealous (compare Deuteronomy 4:24; Deuteronomy 6:15; Exodus 20:5; Exodus 34:14) with what was foreign, seeking to false gods and false religion, they provoked Him to anger with their idolatrous ways and behaviour.
For ‘abominations' see Deuteronomy 7:25; Deuteronomy 27:15; 2 Kings 23:13.
It is a sad fact that when God prospers men they soon forget Him. It only takes a little wealth and the opportunity for pleasure for our consecration to go out of the window.
They sacrificed unto demons, which were no God,
To gods that they knew not,
To new gods that came up of late,
Which your fathers dreaded not.
Of the Rock which begat you (thee) you are unmindful,
And have forgotten God that gave you (thee) birth in pain.'
In preference to God they turned to demons (compare Psalms 106:37; 1 Corinthians 10:20) which were no god, they sacrificed to them, and to gods that they had never had anything to do with, to new fangled gods who were not even ancient, gods that their fathers had never feared, and they forgot their God from of old Who had brought them into being, Who had begotten them and Who had borne them in pain (He had been both father and mother). They dallied with novelties and with the occult. The begetting and bringing forth in pain may refer to the deliverance from Egypt.
We may not dally with these. But we dally with our idols in music and sport, in travel and entertainment, and we forget our responsibility towards the One Who was crucified for us.