John Wesley on Deuteronomy 21:19

His father and mother - The consent of both is required to prevent the abuse of this law to cruelty. And it cannot reasonably be supposed that both would agree without the son's abominable and incorrigible wickedness, in which case it seems a righteous law, because the crime of rebellion against his own parents did so fully signify what a pernicious member he would be in the commonwealth of Israel, who had dissolved all his natural obligations. Unto the elders - Which was a sufficient caution to preserve children from the malice of any hard - hearted parents, because these elders were first to examine the cause with all exactness, and then to pronounce the sentence.