It is the Pharisees who believed in the Resurrection, not the Sadducees. That is something that is peculiar to their sect alone.
The Scripture plainly shows that within Judaism there has always been a belief in Eternal Life. I will point you in the direction of the Psalms because you will find plenty of references. If you start with Psalm 1 and then work your way through there are a heap of references to Yahweh looking after the righteous, but not the wicked who will perish.
If you are Catholic you might want to search for references in Sirach (Ecclesiasticus) as well as the Book of Wisdom. I have a gem from Sirach:
“Grubs and worms will have him as their legacy, and the man who knows no shame shall lose his life.” (Ecclesiasticus 19:3)
This verse reminds me of spiritual death.
Maggie