Here's a quote from Luther on the human capacity to cultivate civil righteousness, the capacity of all people to develop virtue and be relatively good people. Reformed theology speaks similarly when it talks of common grace. Luther is careful to distinguish this from being truly righteous before God.
We must distinguish between the theological and the civil standpoints. God approves also the rule of the ungodly; he honors and rewards virtue also among the ungodly, but only in regard to the things of this life and things grasped by a reason which is upright from the civil standpoint; whereas the future life is not embraced in such reward. His approval is not with regard to the future life. We believe that man without the Holy Spirit is altogether corrupt before God, though he may stand adorned with all heathen virtues, as moderation, liberality, love of country, parents and children, courage and humanity. The declarations of the Holy Scriptures prove the same thing. The statement in the fourteenth Psalm is sweeping enough when it says, “The Lord looked down from heaven upon the children of men, to see if there were any that did understand, and seek God. They are all gone aside, they are all together become filthy; there is none that doeth good; no, not one. Paul says, “God hath concluded them all in unbelief.” Christ says, “Without me ye can do nothing.”Quoted in DEVOTIONAL READINGS from LUTHER’S WORKS for EVERY DAY OF THE YEAR by REV. JOHN SANDER, L. H. D.