This completes the sentence that began in verse 25 with the condition that is contrary to fact, "If I have not established ... and if I have not fixed ... earth." God said this to assure his people that he will not reject them and he will bring someone to rule over them. Alternate translation: "Just as I have established the covenant ... so I will never reject the descendants ... and I will bring" (See: [[rc://en/ta/man/translate/figs-hypo]])
The abstract noun "captivity" can be translated as a verbal clause. See how similar words are translated in [Jeremiah 29:14](../29/14.md). Alternate translation: "free them from their captivity" or "free them from those who had captured them" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])