EXACTLY
God is NOT the God of the dead, for HE is the GOD of the LIVING
What is the context, David.
I can see you are struggling with the section of text you posted.
"YOU DO NOT UNDERSTAND THE SCRIPTURES"
The very passage they cited (Deut 25:5) illustrates resurrection by representation. The role of the
goel, or kinsman-redeemer (Christ Himself), was to raise up a “seed” a new life in the name of the deceased.
"NOR THE POWER OF GOD" The promises of God are not undone by the seemingly final human reality of death!
The power of God is demonstrated in His ability to raise the dead, something the Sadducees denied.
You have the wrong context for your belief.
Try and find a NT teaching where death means the release of an ethereal immortal wafting essence.
Good luck!