Mark 12:26
Mark 12:2626But concerning the dead rising, have you not read about the burning bush in the Book of Moses, how God told him, ‘I am the God of Abraham, the God of Isaac, and the God of Jacob’?
The Watchtower reads the burning-bush quotation as a promise of future resurrection — the patriarchs will live again because God remembers them and intends to raise them. The present-tense form of "I AM the God of Abraham" is treated as a covenant promise rather than a claim that the patriarchs are currently alive. Soul-sleep doctrine requires this reading.
The argument Jesus is making against the Sadducees only works if the present-tense "I AM" is doing real work. He cites — spoken to Moses centuries after Abraham, Isaac, and Jacob had died — and treats God's present-tense self-identification as proof that the patriarchs are still in relationship with God. If they were non-existent, God would have said "I was their God." Jesus's use of the present tense is the load-bearing word. Pair with (Luke's parallel adds "for to him all are alive") and the case against soul sleep is built from Jesus's own argumentation, not from a proof-text inserted at a tangent.