God’s covenant with David is eternal. Hear the word from the prophet Jeremiah…
“Thus saith the LORD; If ye can break My covenant of the day, and My covenant of the night, and that there should not be day and night in their season; then may also My covenant be broken with David My servant, that he should not have a son to reign upon his throne; and with the Levites the priests, My ministers.
As the host of heaven cannot be numbered, neither the sand of the sea measured: so will I multiply the seed of David My servant, and the Levites that minister unto Me. Moreover the word of the LORD came to Jeremiah, saying, Considerest thou not what this people have spoken, saying, The two families which the LORD hath chosen, He hath even cast them off? Thus they have despised My people, that they should be no more a nation before them.
Thus saith the LORD; If My covenant be not with day and night, and if I have not appointed the ordinances of heaven and earth; then will I cast away the seed of Jacob, and David My servant, so that I will not take any of his seed to be rulers over the seed of Abraham, Isaac, and Jacob: for I will cause their captivity to return, and have mercy on them.” Jeremiah 33:20-26 (KJB)
As is God’s covenant with David; that is Judah and Israel; so too is His covenant of the cross. For all who will be redeemed to God from sin, must come to Him through the shed blood of Jesus Christ – the death, burial, and resurrection.