The key to the Christian hope is the resurrection of the dead. It is the only hope we have, without out the resurrection there’s no hope.
There was a group of guys called Sadducees who didn’t believe in the resurrection, and they wanted to trick Jesus, and they were mocking him a little for believing in such a thing.
Jesus’ response, his proof for the resurrection, is what God said in the Old Testament
‘I am the God of Abraham, and the God of Isaac, and the God of Jacob’? He is not God of the dead, but of the living.”
His point is, God IS the God of these dead saints. If there’s no resurrection, they are dead and gone forever. But, they are not dead and gone forever, they will be back, so God is still their God.
This is Jesus’ argument, the proof He puts forth to argue for the resurrection (and then He went out and was resurrected Himself).
You can trust in God, and you can have hope too! Just trust in Jesus and you too have the hope of the resurrection… this life isn’t the end!