Christians why does God need the blood of JESUS GOD on a cross in order to forgive the sins?

I don't get God father demanding to JESUS God to die on a cross to forgive the sins if that blood was lost since nobody washed with that blood, in the OT, the blood was burnt and offered to GOD but the jesus blood was wasted because he died on a cross and nobody burn his blood or say I offer you the blood of Jesus to forgive my sins, what kind of God demands someone to die on a cross because he wants his blood?