I. Whence this mercy promised shall take rise (v. 18): God will be jealous for his land and pity his people. He will have an eye, 1. To his own honour, and the reputation of his covenant with Israel, by which he had conveyed to them that good land and had given in the value of it very high; now he will not suffer it to be despised nor disparaged, but will be jealous for the credit of his land, and the inhabitants of it, who had been praised as a happy people and therefore must not lie open to reproach as a miserable people. 2. To their distress: He will pity his people, and, in pity to them, he will restore them their forfeited comforts. God's compassion is a great encouragement to those that come humbly to him as penitents and as petitioners.