John Calvin Commentary Genesis 26:11

"And Abimelech charged all the people, saying, He that toucheth this man or his wife shall surely be put to death." — Genesis 26:11 (ASV)

And Abimelech charged all his people. In denouncing capital punishment against anyone who should do injury to this stranger, we may suppose him to have issued this edict as a special privilege, for it is not customary to avenge every kind of injury so rigidly. From where, then, did this disposition arise in the king to prefer Isaac to all the native inhabitants of the country, and almost to treat him as an equal, if not that some portion of the divine majesty shone forth in him, which secured for him this degree of reverence?

God, also, to assist the weakness of his servant, inclined the mind of the heathen king, in every way, to show him favor. And there is no doubt that his general modesty induced the king to protect him so carefully; for he, perceiving him to be a timid man, who had been on the verge of saving his own life at the expense of his wife's ruin, was more inclined to assist him in his dangers, so that he might live in security under his government.