For all that do these things are an abomination. First, he would have the authority of God act as a rein to guide them; and then sets before them that vengeance which they were soon about to see inflicted upon the heathen, nay, of which they were themselves to be the executioners and ministers. For since it could not be a matter of the slightest doubt, but that the inhabitants of the land of Canaan were rooted out from their peaceful habitations only by God's hand, he assigns as the cause of this destruction that they had polluted themselves and their country by these blasphemous and abominable superstitions. By this striking example, then, he deters them from imitating the sins which facts themselves shewed to be thus severely punished. Thus Paul admonishes believers to seek diligently to avoid the sins which provoke God's wrath against the disobedient. (Ephesians 5:6.)

For all that do these things are an abomination to the Lord,.... Not that do all these things, but whoever does any of them, as Jarchi notes; all such persons that use such unlawful methods, or any of them, to gain knowledge; and likewise all those that consult them, and make use of them; and especially it must be very abominable in the people of Israel to encourage such persons and practices, who had the knowledge of the true God, and him to consult on all occasions; had his law and testimony to attend unto as the rule of their conduct, and his prophets to advise with in matters of difficulty; see Isaiah 8:20.
and because of these abominations the Lord thy God doth drive them out from before thee; as well as other sins mentioned in Leviticus 18:24 and, as before observed from Cicero, all nations have been addicted to the arts of divination here condemned.

Whoever did this was an abomination to the Lord, and it was because of this abomination that He rooted out the Canaanites before Israel (cf. Leviticus 18:24.).