Here God opposes the constancy of his faithfulness to their perverse murmurings, of which he had complained; and he again adduces the similitude previously brought forward: "lf, then, I have not fixed my covenant, or if there is no covenant as to the day and the night, -- if there are no laws as to heaven and earth, then I shall now cast away the seed of Jacob and the seed of David: but if my constancy is ever conspicuous as to the laws of nature, how is it that ye ascribe not to me my due honor? For I am the same God, who created the heaven and the earth, who fixed all the laws of nature which remain unchangeable, and who also have made a covenant with my Church. If my faithfulness as to the laws of nature changes not, wily should it change as to that sacred covenant which I have made with my chosen people?"

We now see the reason why God so often confirmed a thing in itself sufficiently clear, even because the contest with the obstinate hopelessness of the people was difficult. For they thought that they were rejected without any hope of deliverance, when God punished them only for a time for their wickedness, as they deemed their exile to be without a return.

He mentions the seed of Jacob first, because it had been said to Abraham, For thy seed, and the same promise was repeated to Jacob. (Genesis 26:4; Genesis 28:14) He afterwards adds the seed of David, because an especial promise was afterwards given to David, (2 Samuel 7:12, 13:) Then also the seed of David, he says, will I reject, that I should not take of his seed to rule over the seed of Abraham, Isaac, and Jacob: he now fitly joins together what might have seemed unconnected; for he says, that there would be always some of David's posterity to rule over all the tribes. God, therefore, thus preserved his Church when he set a king over his Church; or a kingdom, as we have said, is inseparable from the safety of the people.

He lastly adds, For I will restore their captivity. This obviated the diffidence of the people: for an objection was ready at hand, "What can this mean? for the ten tribes have been already led away into distant regions, and are scattered; a part also of the kingdom of Judah has been cut off; and what remains is not far from entire ruin." Hence God calls their attention to the hope of deliverance, as though he had said, that they were acting foolishly, because they were thus hasty, for their expectation ought to have remained in suspense until the time prescribed, that is, till the end of the seventy years, according to what we have before seen, when the Prophet spoke against impostors who boasted of a quick return. He therefore tells them that they ought patiently to bear their exile, until the full time of their deliverance came. And he points out the fountain or cause of their deliverance when he says, I will have mercy on them, as though he had said, that the very salvation whieh he promised to the people depended on his gratuitous mercy.