Jeshurun grew fat and abandoned the Rock (Deuteronomy 32:15–18)

Says "But Jeshurun grew fat and kicked" and "abandoned the God who made him and scorned the Rock of his salvation" (32:15, BSB). The Hebrew turns to "you" in the middle of the line. The Septuagint adds "and Jacob ate and was filled."

The text printed here follows the MT without the addition, with medium confidence (see the textual note on 32:15).

Says "They provoked His jealousy with foreign gods" (32:16, BSB). "They sacrificed to demons, not to God, to gods they had not known" (32:17, BSB). לַשֵּׁדִים (lashedim, "to demons") is a rare word, found again in Ps 106:37; BDB takes it as a loanword from Assyrian (pp. 993–994). See the Hebrew note on 32:15–18 and the historical note on the demons and new gods.

Says "You ignored the Rock who brought you forth; you forgot the God who gave you birth" (32:18, BSB).

Uncertain Whether Paul alludes to 32:17 in 1 Cor 10:20. This commentary leans, with the Greek note on 32:17, that he does: the same pairing of "demons" and "not God" comes in a passage that moves from Israel's idolatry to pagan sacrifice and speaks two verses later of provoking the Lord to jealousy (1 Cor 10:22; compare Deut 32:21). The alternative is that the pairing was a common way of speaking about idol sacrifice, since Ps 106:37 uses it too.