It will always give a Christian the greatest calm, quiet, ease, and peace, to think of the perfect righteousness of Christ. How often are the saints of God downcast and sad! I do not think they ought to be. I do not think they would if they could always see their perfection in Christ. There are some who are always talking about corruption, and the depravity of the heart, and the innate evil of the soul. This is quite true, but why not go a little further, and remember that we are “perfect in Christ Jesus.” It is no wonder that those who are dwelling upon their own corruption should wear such downcast looks; but surely if we call to mind that “Christ is made unto us righteousness,” we shall be of good cheer. What though distresses afflict me, though Satan assault me, though there may be many things to be experienced before I get to heaven, those are done for me in the covenant of divine grace; there is nothing wanting in my Lord, Christ hath done it all. On the cross he said, “It is finished!” and if it be finished, then am I complete in him, and can rejoice with joy unspeakable and full of glory, “Not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith.” You will not find on this side of heaven a holier people than those who receive into their hearts the doctrine of Christ’s righteousness. When the believer says, “I live on Christ alone; I rest on him solely for salvation; and I believe that, however unworthy, I am still saved in Jesus;” then there rises up as a motive of gratitude this thought—“Shall I not live to Christ? Shall I not love him and serve him, seeing that I am saved by his merits?” “The love of Christ constraineth us,” “that they which live should not henceforth live unto themselves but unto him which died for them.” If saved by imputed righteousness, we shall greatly value imparted righteousness.
Spurgeon, Charles H. Morning and Evening : Daily Readings. Complete and unabridged; New modern edition., January 31 AM. Peabody, MA: Hendrickson Publishers, 2006.