en_tn_condensed/jer/02/21.md

I planted you as a choice vine, completely from pure seed

God speaks of making his people into a great nation in Canaan as if they were the seed of a grapevine that he had planted. AT: "I, Yahweh, started you with a very good beginning, like a farmer who uses excellent seed to plant the best kind of vine" (See: rc://en/ta/man/translate/figs-metaphor)

a choice vine

"a vine of very good quality"

completely from pure seed

Here "pure seed" is the best seed that has not been mixed with seed that is not good. AT: "that grew from excellent seed"

How then have you have changed yourself into a corrupt, worthless vine?

God uses this question to rebuke his people for changing and becoming like a corrupt worthless vine. AT: "But you have changed yourself into a corrupt, worthless vine!" (See: rc://en/ta/man/translate/figs-rquestion)