Charles Ellicott Commentary Deuteronomy 32:21

"They have moved me to jealousy with that which is not God; They have provoked me to anger with their vanities: And I will move them to jealousy with those that are not a people; I will provoke them to anger with a foolish nation." — Deuteronomy 32:21 (ASV)

“They have made me jealous with a no-god;
They have provoked me with their vanities:
And I will make them jealous with a no-people;
With a foolish nation will I provoke them.”

Saint Paul comments on this in Romans 10:0, as proving that Israel was informed of the calling of the Gentiles, and compares Isaiah 65:1, “I was found of them that sought me not. I made myself manifest unto those that inquired not after me.”

Rashi quotes, perhaps not quite inappropriately, Isaiah 23:13, and gives this explanation: “A no-people,” that is, a nation without a name; as it is said, “Behold the land of the Chaldseans: this people was not.”