1. In that God should be willing to accept of satisfaction from the hands of our surety, which he might have demanded of us. This appears from what has been before observed, namely, that the debt which we had contracted was not of the same nature with pecuniary debts, in which case the creditor is obliged to accept of payment, though the overture hereof be made by another, and not by him that contracted the debt: whereas the case is different in debts of obedience to be performed, or punishment to be endured; in which instances, he, to whom satisfaction is to be given, must accept of one to be substituted in the room of him from whom the obedience or sufferings were originally due; otherwise, the overture made, or what is done and suffered by him, pursuant thereunto, is not regarded, or available to procure a discharge for him, in whose room he substituted himself. God might have exacted the debt of us, in our own persons, and then our condition had been equally miserable with that of fallen angels, for whom no mediator was accepted, no more than provided. 2. The grace of God farther appears, in that he provided a surety for us, which we could not have done for ourselves; nor have engaged him to perform this work for us, who was the only person that could bring about the great work of redemption. The only creatures who are capable of performing perfect obedience, are the holy angels; but these could not do it, for, as has been before observed, whoever performs it must be incarnate, that they may be capable of paying the debt, in some respects, in kind, which was due from us; therefore they must suffer death, and consequently have a nature which is capable of dying; but this the angels had not, nor could have, but by the divine will. Besides, if God should have dispensed with that part of satisfaction, which consists in a subjection to death, and have declared, that active obedience should be sufficient to procure our justification; the angels, though capable of performing active obedience, would, notwithstanding, have been defective therein; so that justice could not, in honour, have accepted of it, any more than it could have dispensed with the obligation to perform obedience in general; because it would not have been of infinite value; and it is the value of things that justice regards, and not barely the matter of perfection thereof in other respects: so that it must be an obedience that had in it something infinitely valuable, or else it could not have been accepted by God, as a price of redemption, in order to the procuring our justification: and this could be performed by none but our Lord Jesus Christ, the glorious author and procurer of this privilege.