Albert Barnes Commentary Jeremiah 2:21

"Yet I had planted thee a noble vine, wholly a right seed: how then art thou turned into the degenerate branches of a foreign vine unto me?" — Jeremiah 2:21 (ASV)

A noble vine – Properly, a Sorek vine , which produced a red wine (Proverbs 23:31) and had a lasting reputation (Genesis 49:11).

A right seed – literally, “a seed of truth,” i.e., true, genuine seed, not mixed with weeds, nor with seed of an inferior quality. .

How then are you turned – Or, How then have you changed yourself to me (i.e., to my hurt or vexation) into the degenerate branches of a strange vine? The stock, which was God’s planting, was genuine, and of the noblest sort: the wonder was how such a stock could produce shoots of a totally different kind (Deuteronomy 32:32).