The Bible does not mention cremation directly. What we know about burial customs from the Bible is that burning of the body is always associated either with pagan practices or as a sign of dishonoring the body. Until recently Christians almost universally practiced burial as a sign that we honor the human body and because we believe in the resurrection of the body. That’s a key point. Christians don’t just believe in the resurrection of “the person” or of “the soul” but of the physical body. In fact, the early Christians called their burial places “sleeping places.” The Greek word they used became the foundation for the English word “cemetery.”

I cannot say that cremation is a sin. And certainly cremating the body will not stop God from raising that person from the dead. If you can raise the dead, you can raise the dead. The condition of the body post-death does not change that fact. However, I believe that burial is more consistent with the Christian faith than cremation. Sometimes the situation at death mandates cremation, but where possible, I always recommend burial of the body, not burning it and then burying the ashes. That’s how I want things handled when I die if at all possible.

See Acorns to Oak Tree: How Are the Dead Raised?