"Human reason has the law for its object, thinking, 'I have done this; I have not done that.' But faith in itself has no object but Jesus Christ, the Son of God, given up to death for the sins of the whole world. It does not say, 'What have I done? In what have I offended? What have I deserved?' It says, 'What has Christ done? What has he deserved?' He has redeemed you from your sin, from the devil and from eternal death."
Martin Luther, Commentary on Galatians. Crossway, 1998: pg 71-72.