To a penitent heart in the first place belongs, that you confess your sins and experience sorrow and penitence on account of them. By nature no man can know his sins, nor can he produce penitence in his heart concerning them; this must above all be sought of God. We men are by nature much too blind, too indifferent, too inconsiderate, too selfrighteous, too much possessed with self-love and self-interest, than to be inclined and capable penitently and uprightly to confess ourselves guilty of all sins. Wherefore above all things bend your knees before God and call upon him, that He might open your eyes that you may thoroughly know the multitude and greatness of your sins. Pray with the blessed David: "Search me, O God, and know my heart; try me, and know my thoughts; and see if there be any wicked way in me, and lead me in the way everlasting." Hereupon take the holy ten commandments and make a careful examination of your whole life in accordance with them. Then you will know that you are a sinner. For as a man cannot see a spot on his face without a glass, neither can he know his sins without beholding himself in the glass of the holy ten commandments. For sin is every work, every word, yea, every thought, which is against God's commandments; for sin consists in the performance of that which God has forbidden, or in the omission of that which He has commanded to be done. But you must not only regard the gross external sins, but also the internal secret sins, departures from God's commandments, which have taken place in the heart through evil thoughts and desires. If you will examine yourself thus in constant prayer, you will discover that you have not feared, loved and trusted God as He requires, that you have not so heartily and confidently called upon God, prayed, praised and given thanks, that you have not kept His Word so holy, heard and learned it, as you should have done. You will find that you have not honored and loved your parents and superiors, but have been disobedient and murmured against them; you will find that you have sinned against your neighbor in anger, hatred, revenge and irreconcilableness, with unchaste thoughts and desires, envy, illwill, avarice, an earthly mind or with slanderous words, in short, you will find that you have not so uprightly and heartily loved your neighbor as yourself, that much more selfishness, the seeking of your own interests or your own honor has been the motive to all your actions. With these and other sins you have surely deserved the wrath of God, temporal and eternal punishment, if God would deal with you according to His stern righteousness. From these sins which you perceive in yourself you can draw the conclusion how impure and depraved your heart is, from which these sins flow, for as the water, so the spring, and by the fruits we know the tree. Hence you will come to the knowledge of original sin.