Jamieson, Fausset and Brown on Matthew 10:21

21. And the brother shall deliver up the brother to death, and the father the child: and the children shall rise up against their parents, and cause them to be put to death--for example, by lodging information against them with the authorities. The deep and virulent hostility of the old nature and life to the new--as of Belial to Christ--was to issue in awful wrenches of the dearest ties; and the disciples, in the prospect of their cause and themselves being launched upon society, are here prepared for the worst.