God of the Living
Jesus rested His argument primarily on the fact that God had said “I am the God of Abraham,” etc., as opposed to “I was.” If God was currently the God of the patriarchs when He spoke to Moses, and if “God is not the God of the dead but of the living,” then the patriarchs must still have been alive at that time (which the Sadducees denied), even though they had died physically.
Ryan McGraw, By Good and Necessary Consequence (Grand Rapids, MI: Reformation Heritage Books, 2012), 0