… God does not want to be known except through Christ; nor, according to John 1:18, can He be known any other way. Christ is the Offspring promised to Abraham; on His God founded all His promises. Therefore Christ alone is the means, the life, and the mirror through which we see God and know His will.
Through Christ God announces His favor and mercy to us. In Christ we see that God is not a wrathful taskmaster and judge but a gracious and kind Father, who blesses us, that is, who delivers us from the Law, sin, death, and every evil, and endows us with righteousness and eternal life through Christ. This is a sure knowledge of God and a true divine conviction, which does not deceive us but portrays God Himself in a specific form, apart from which there is no God.
Martin Luther Luther’s Works 396