Accordingly each Christian continues to experience in his heart times of the Law and times of the Gospel. The times of the Law are discernible by heaviness of heart, by a lively sense of sin, and a feeling of despair brought on by the Law. These periods of the Law will come again and again as long as we live. To mention my own case. There are many times when I find fault with God and am impatient with Him. The wrath and the judgment of God displease me, my wrath and impatience displease Him. Then is the season of the Law, when "the flesh lusteth against the Spirit, and the Spirit against the flesh."
The time of grace returns when the heart is enlivened by the promise of God's mercy. It soliloquizes: "Why art thou cast down, O my soul? and why art thou disquieted within me? Can you see nothing but law, sin, death, and hell? Is there no grace, no forgiveness, no joy, peace, life, heaven, no Christ and God? Trouble me no more, my soul. Hope in God who has not spared His own dear Son but has given Him into death for thy sins." When the Law carries things too far, say: "Mister Law, you are not the whole show. There are other and better things than you. They tell me to trust in the Lord."
There is a time for the Law and a time for grace. Let us study to be good timekeepers. It is not easy. Law and grace may be miles apart in essence, but in the heart, they are pretty close together. In the heart fear and trust, sin and grace, Law and Gospel cross paths continually.
Martin Luther, Commentary on the Epistle to the Galatians; (Vs. 3:23);(Kindle Edition).