Thank you for contacting BibleAsk.
Cremation was practiced in ancientl times, but it was not practiced by the Old or New Testament believers. In the Bible days, it was the custom to bury the dead in the ground or caves (Genesis 23:19; 35:19; 2 Chronicles 16:14; Matthew 27:60-66).
God buried Moses Himself (Deut 34:5-8; Jude 1:9). Abraham, purchased the first family cemetery, and many family members were buried there (Gen 15:15; 23:1-20; 25:9-10; 35:8,19,29; 47:29-31; 49:28-33; 50:1-14). Joseph wanted his bones be carried out of Egypt, so he could be buried in Canaan, though they had to keep his embalmed body in a coffin for about 200 years until the Exodus (Gen 50:24-26; Ex 13:19; Josh 24:32). David, was buried; and the location of his tomb was still well known 1000 years later in Jerusalem (I Kings 2:10; 11:43; Acts 2:29; 13:36).
The Old Testament mentions people being burned to death (1 Kings 16:18; 2 Kings 21:6) and of human bones being burned (2 Kings 23:16-20), but these are not examples of cremation.
In the New Testament, Christians buried their dead. Martha and Mary buried Lazarus. And the family or friends of the rich man also buried him (Luke 16:22; Matt 8:22; 27:1-10,57-60; John 11:33-44; Acts 5:1-11; 8:2). The Lord Jesus Christ of Nazareth was buried. Even though His body had been mangled, and there was no funeral, they still took the time to prepare His body for burial (Isaiah 53:9; Matt 27:57-60; Mark 15:43-46; Luke 23:50-53; John 19:38-42; Acts 13:29; I Cor 15:4).
God’s judgment on Adam at death was to return to the ground from which he had been taken. He was to return to dust, not be turned into ashes (Gen 3:19; Job 34:15; Ps 104:29; Eccl 3:20; 12:7; Dan 12:2). Burning a body to ashes is what will happen to the devil and his children at the end of the world (Gen 3:1-7; Job 1:1-22; 2:1-10; Matt 8:29; 15:22; 25:41; 27:5).
If a believer got cremated beyond his will, God will still be able to resurrect him for the Lord is the Creator and He will grant him a new glorified body at the Resurrection Day at His second coming (1 Corinthians 15:35-58; 1 Thessalonians 4:16).