John Gill Commentary Ezekiel 23:39

"For when they had slain their children to their idols, then they came the same day into my sanctuary to profane it; and, lo, thus have they done in the midst of my house." — Ezekiel 23:39 (ASV)

For when they had slain their children to their idols This explains more clearly what is before said, that by causing their children to pass through the fire was a slaying them; and that their passing through it "for them" was for their idols, and unto them; see (Ezekiel 23:37).

And how when they had been guilty of such shocking wickedness, then they came the same day into my sanctuary to profane it; not that they came into the temple on purpose to profane it; but coming into it, being themselves defiled with the murder of their infants, and offering sacrifices to idols, or performing a hypocritical service to the Lord, this was in the event a profanation of the sanctuary.

And, lo, thus they have done in the midst of mine house; set up idols there, and worshipped them; as they did in the temple itself, in the times of Ahaz and Manasseh; see (Jeremiah 7:30).