From Jonathan Edwards, "Profitable Hearers of the Word," in The Works of Jonathan Edwards, vol. 14: Sermons and Discourses, 1723-1729, ed. Kenneth P. Minkema (Yale University Press, 1997), 266-7:
...I would premise, negatively, that there are no degrees of imputed righteousness, but that all saints are alike justified in the sight of God by the righteousness of Christ. As there are no degrees in the same person with the represent to this, but he is as much justified the first moment of his conversion as ever he is, how much soever he may increase in holiness afterwards; so neither is there any difference in this respect in different persons.
The weakest saint is as much justified in the sight of God as the strongest. He that has but a spark of grace in his heart, the lowest degree of the sanctifying spirit, has his sins as much pardoned, and Christ's satisfaction and righteousness as much imputed to him, as Moses or Elijah or the apostle Paul had, yea, as much as the saints of heaven have.
'Tis very evident because all the sins of every believer, as soon as ever he believes, are pardoned; and if they are all pardoned and blotted out, cast into the depths of the sea, so that they shall be remembered no more, then there can be no degrees of pardon. If sins are so pardoned that God's anger is all ceased, they can't be more pardoned. Christ's death has fully satisfied for the sins of all believers, is of as much virtue to satisfy for the sins of one as of another. So his righteousness is wrought out for one saint as much for another.
'Tis the same perfect righteousness imputed to everyone, and if it be really imputed to all, there is as much as it can be; there can be no degrees of imputation of the same thing. If it be one covenant by which they have their righteousness, then their righteousness must be the same.