…to give unto them beauty for ashes, the oil of joy for mourning, the garment of praise for the spirit of heaviness… – Isaiah 61:3
True hearts mourn not only for their past transgressions, but they also sorrow over their present imperfections. If you are what you should be, dear friend, I am quite certain you see a great deal in yourself to grieve over. You cannot live as you would live. Whenever I meet with a person who feels that he is perfect, I conceive at once that he has not yet attained even a remote conception of what true perfection must be. The savage of Australia is satisfied with his weapons of war so long as he has never seen a rifle or heard of a cannon: to him his hovel is a model of architecture, for he has never heard of a cathedral or a palace… Men know not what God is, nor the infinity of His perfections, nor the majesty of His purity, else, when highest would they cry, “Higher, higher, higher,” and mourn because they have not yet attained, and need still to mount as on eagle’s wings. Brethren, I speak for you all when I say, there is not a day in which our service satisfies us, not a deed we have ever performed that contents us. We see our spots, and would fain wash them out with tears if we could, though we bless God they are removed by the precious blood of Jesus. Those are among the blessed who mourn because they cannot live a perfect life as they desire. To mourn after more holiness is a sign of holiness, to mourn after greater conformity to the image of Christ proves that we are already in a measure conformed thereunto; to sigh after more complete subordination of our entire life to the will of God is a mourning for which Jesus Christ will bring rich comfort. ~ C.H. Spurgeon
https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1016.cfm