...those who deny that there is a resurrection...
The Sadducees insisted on the literal meaning of the text, following only the first five books of the Bible (excluding the Prophets, the Wisdom books, and the Historical books from their sense of "Scripture"). They also insisted there was no bodily resurrection, no spirits, and no demons. They had some other teachings - they were Pelagian before Pelagius - but these were their two main hallmarks: Scripture and Resurrection. It is these that are most beloved today. As regards the Bible and the Resurrection, world has become filled with Sadducees.
Most people insist what they see as a literal reading of the Bible: they refuse to allow the Church to teach her teachings without asking, "How is that in the Bible?" They deny the idea of oral tradition, of teachings evolved from discussions about the Bible rather than some odd idea of Sola Scriptura. While they are, often, interpreting the Bible in their own way (and insisting that's the literal meaning) they ignore that for 4,000 years the Jewish community, and for 2000 years the Christian community have been engaged in discussions about what it means. These are two different discussions one growing out of and beyond the other. One cannot set up camp outside them. Even in the Churches this can be the case, where persons will reject the teachings of the Church based (a la Luther) on their private sense of what the scripture means... but calling it the "literal meaning of the text". These are Sadducees in spirit. The Jesus Seminar people are Sadducees, insisting that most of the New Testament is Oral Traditions accreted onto some sort of Ur Jesus Story.
Many Christians are Sadducees in regards to the Resurrection. Christian theology is very clear: humanity is both soul and body. Angels are pure spirit, with no physical body. Animals are pure matter with no spiritual content. (This is why all dogs do not go to heaven, contra certain evangelical silliness.) Man is both a Soul and a Body, as Jesus was both God and Man. We are not so much as a Body with a Soul as we are a Soul with a Body. As a person, Jesus was Eternal, Uncreated Beingness in an immortal Soul-Mortal Body unity. And you and I are that latter part: an Immortal (meaning undying) and Mortal (meaning dying) unity.
Many Christians of the more conservative sort (and I've heard this in Orthodox and Catholic conversations as well as Protestant) make us out to be Spirits that happen to have bodies right now. "When we die we will all go to heaven." "Grandma's an Angel with Jesus, now." While we certainly believe the Saints are granted a foretaste, it is only in the General Resurrection and after the Judgement that, by God's mercy, most of us will "get to go to heaven". But when we do, it will be in our bodies, in the flesh. This mortal flesh will put on immortality and, whatever he is, we shall be as Jesus is. This is why the Orthodox do not cremate, although I think a mortal body can corrupt in a fire just as easily as in the dirt.
Many Christians of the more progressive sort deny any spiritual function at all. Honestly, I have no idea what they're doing in the Church b/c they're functional Atheists, as far as I'm concerned. If there is no resurrection for all of us there is none for Jesus. And if Jesus didn't rise, then this is all malarky. Again, the Jesus Seminar fits into this category so they are doubly Sadducees.
It's easy to pretend there is no resurrection. But why? There's no hope, there's nothing to live for, no reason to imagine good to have a point. What makes me giggle is the idea that you can then say "there is still a reason to do good in the world" and "there is a literal definition of things that are good." The world is filled with Sadducees. (Easy mnemonic: because they don't believe in the resurrection, they're Sad, you see?)
If your God is not the God of the Living, then why bother?