What did the Law require be done with the body of a hanged man?
Deuteronomy 21 required that if an executed man's body was hanged on a tree, it must not remain there overnight; it had to be buried that same day. The reason given is that one hanged is accursed of God, and the land must not be defiled.
Les explains that the Law's requirement is found in Deuteronomy 21:22-23. If a man had committed a sin worthy of death, was put to death, and was hanged on a tree, his body was not to remain all night upon the tree; it was to be buried that day. The reason given is that he who is hanged is accursed of God, so the land would not be defiled. Les connects this to why the Jews were in such a hurry to get Jesus off the cross, because He had been hanged on a tree.
And if a man have committed a sin worthy of death, and he be to be put to death, and thou hang him on a tree:
His body shall not remain all night upon the tree, but thou shalt in any wise bury him that day; (for he that is hanged is accursed of God;) that thy land be not defiled, which the LORD thy God giveth thee for an inheritance.