Romans 9:12

This reasoning, then, he says, must be received not only concerning Isaac, but concerning Jacob as well. For Rebecca too, he says, did not bring forth her offspring according to the order of fleshly nativity. For when she had conceived twins from a single act of intercourse with Isaac, before the birth had yet taken place, and before any deeds of the boys, good or evil, had been done among men, the divine election is held toward Jacob, and it is said, "that the elder shall serve the younger," and, "Jacob I loved, but Esau I hated."

"For the children being not yet born, neither having done any good or evil, that the purpose of God according to election might stand, not of works, but of him that calleth, it was said unto her, the elder shall serve the younger. As it is written, Jacob have I loved, but Esau have I hated." What was the cause then why one was loved and the other hated? why was it that one served, the other was served? It was because one was wicked, and the other good. And yet the children being not yet born, one was honored and the other condemned. For when they were not as yet born, God said, "the elder shall serve the younger." With what intent then did God say this? Because He doth not wait, as man doth, to see from the issue of their acts the good and him who is not so, but even before these He knoweth which is the wicked and which not such. And this took place in the Israelites' case also, in a still more wonderful way. Why, he says, do I speak of Esau and of Jacob, of whom one was wicked and the other good? For in the Israelites' case, the sin belonged to all, since they all worshipped the calf. Yet notwithstanding some had mercy shown them, and others had not. The clearing up then of the whole passage, to give the whole sense summarily, is here brought out by that blessed person. But that this may be clearer, let us investigate the things he says also one by one; this knowing, that what the blessed Paul aimed at was, to show by all that he said that God only knoweth who are worthy, and no man whatever knoweth, even if he seem to know ever so well, but that in this sentence of his there are sundry aberrations. For He that knoweth the secrets of the hearts, He only knoweth for a certainty who deserve a crown, and who punishment and vengeance. […]

No one could say that Jacob had conciliated God by meritorious works before he was born, so that God should say this of him.… Nor had Isaac conciliated God by any previous meritorious works, so that his birth should have been promised.… Good works do not produce grace, but are produced by grace.

Third, he sets down the promise, saying, not of works, for no works preceded it, as has been said: but of him who calls, i.e., through the grace of God calling, for it was said to her, i.e., Rebecca, that the elder, i.e., Esau, shall …

As God chose Isaac and Jacob, and rejected Ishmael and Esau, so he might and did choose faith to be the condition of salvation and reject the works of the law. Thus Arminius understands it, De rejectis et assumptis talibus, certa qualitate notatis--Concerning such as are rejected and such as are chosen, being distinguished by appropriate qualities; so John Goodwin.