What does Mark 12:26 mean?

And about the dead being raised—haven’t you read in the book of Moses, in the story about the burning bush, how God said to Moses, ‘I am the God of Abraham, the God of Isaac, and the God of Jacob’?' Mark 12:26 - Modern Text Bible

(Jesus refers to the story of Moses and the burning bush to show that God speaks of Abraham, Isaac, and Jacob as if they’re still alive, even though they died long ago.)