If you do not want to go wrong or be lost, then believe Scripture, which testifies that all men are sinners and that no man living is just in the sight of God.  To become justthey will have to become so through Christ, the blessed Seed, who was promised to Adam, Abraham, and others as He who should crush the serpent's head and redeem the whole world fromthe curse.  This he has done.  He has taken the sin of the whole world upon Himself, has become a curse for us, and in this way has redeemed from the curse all who believe on Him. (Gal.3:13-14)

Such knowledge and faith make a joyous heart which can say with certainty and assurance: I am no longer conscious of any sins, for all of them lie on the shoulders of Christ, and they surely cannot lie on Him and on us at the same time.

(W 49, 125 - E 20 I,490 - SL 7.698 f)

page 1259, What Luther Says: A Practical In-Home Anthology for the Active Christian, compiled by Ewald M. Plass; copyright 1959 by Concordia Publishing House, St Louis, Mo.