When your days are fulfilled to walk with your fathers, I will raise up your offspring after you, one of your own sons, and I will establish his kingdom.Note "walk with your fathers". Other translations say "time to die". The latter implies the end of David as a person. The former suggests that David will live on, walking with his fathers (e.g. Abraham, Isaac, Israel) and doing so immediately, not waiting for the resurrection.
Reminds me of the words of Jesus himself:
"But that the dead are raised, even Moses showed, in the passage about the bush, where he calls the Lord the God of Abraham and the God of Isaac and the God of Jacob. Now he is not God of the dead, but of the living, for all live to him.”© Copyright Bruce M. Axtens, 2015