Incineration
Burning a body is unusual in the Bible, and the cases that do appear are hard ones. Joshua burned Achan and his family after the sin that had cost Israel a battle at Ai. The men of Jabesh-gilead burned the bodies of Saul and his sons after the Philistines had hung them on a wall. King Josiah burned the bones of idol priests on their own altars, and Amos charges Moab with burning the bones of the king of Edom into lime. These are scenes of judgment or grief, and the text does not offer a rule for how Christians should treat the dead. Start with 1 Samuel 31 and Amos 2.
4 verses
Joshua
And Joshua said, Why hast thou troubled us? the LORD shall trouble thee this day. And all Israel stoned him with stones, and burned them with fire, after they had stoned them with stones.
1 Samuel
All the valiant men arose, and went all night, and took the body of Saul and the bodies of his sons from the wall of Bethshan, and came to Jabesh, and burnt them there.
2 Kings
And he slew all the priests of the high places that were there upon the altars, and burned men's bones upon them, and returned to Jerusalem.
Amos
Thus saith the LORD; For three transgressions of Moab, and for four, I will not turn away the punishment thereof; because he burned the bones of the king of Edom into lime: