No where in the Bible does it say that a dead body cannot be cremated. Though the typical way of caring for dead bodies in the Bible was by burial or placing in a tomb, there are no scriptures that tell us we cannot cremate, or burn, dead bodies. What the Bible does tell us is that "All go to the same place; all come from dust, and to dust all return." (Ecclesiastes 3:20). So whether our bodies are buried and slowly become dust, or whether we hurry the process by cremation, doesn't matter. Our bodies will return to dust either way.
Whether we bury or cremate someone will not affect their resurrection. The Bible tells us that everyone who dies will be resurrected back to life! "For as in Adam all die, so in Christ all will be made alive." (1 Corinthians 15:22). Whichever way God sees fit to resurrect mankind, rest assured He knows exactly what He is doing. Nothing we do in regards to how we treat a deceased loved one's body, can interfere with His plan of the resurrection.
One day we will not have to worry or even think about death any longer. In Revelation 21:4 we are told: ‘He will wipe every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away.” What a glorious day that will be!