For the phrase “They sacrificed to demons, not God, to deities they had never known,” see 1 Corinthians 10:20.
Note that this quote in the New Testament is not taken from the Hebrew Bible but from the Greek Septuagint (LXX) which translates into English as “They sacrificed to demons and not to God, to gods they did not know.” (Translation by NETS — for the Greek version see the title’s tooltip)