That the promise might be sure to all the seed, to all them wrapped up in the promise, and so begotten and born. That it might be sure, implying that there is no certain way of salvation for the elect but this; because God can never by other means reconcile us to himself, for his heavenly eyes perceive, yea, they spy faults in the best of our gospel performances; yea, our faith is faulty, and also imperfect: how then should remission be extended to us for the sake of that? But now the righteousness of Christ is perfect, perpetual and stable as the great mountains; wherefore he is called the rock of our salvation, because a man may as soon tumble the mountains before him, as sin can make invalid the righteousness of Christ, when, and unto whom, God shall impute it for justice; Psalm xxxvi. In the margin it is said to be like the mountain of God; to wit, called Mount Zion, or that Moriah on which the temple was built, and upon which it stood; all other bottoms are fickle, all other righteousnesses are so feeble, short, narrow, yea, so full of imperfections; for what the law could not do in that it was weak through the flesh, Christ did for us in the similitude of sinful-flesh. But what could not the law do? Why, it could not give us righteousness, nor strengthen us to perform it. It could not give us any certain, solid, well-grounded hope of remission of sin and salvation.
Wherefore this righteousness being imputed, justice findeth no fault therewith, but consenteth to the extending to the sinner those blessings that tend to perfect his happiness in the heavens.
8. Righteousness by imputation must be first, that in all things Christ may have the pre-eminence. Christ is head of the church, and therefore let him have the highest honour in the soul; but how can he have that, if any precede as to justification before his perfect righteousness be imputed? If it be said, grace may be in the soul, though the soul doth not act it until the moment that justifying righteousness shall be imputed:
I ask, What should it do there before, or to what purpose is it there, if it be not acted? And again, how came it thither, how got the soul possession of it while it was unjustified? or, How could God in justice give it to a person, that by the law stood condemned, before they were acquitted from that condemnation? And I say, nothing can set the soul free from that curse but the perfect obedience of Christ; nor that either, if it be not imputed for that end to the sinner by the grace of God.