Luther on Christ-Centered Theology

It is a principle of the Bible that we are not to inquire curiously into the nature of God. "There shall no man see me, and live," Exodus 33:20. All who trust in their own merits to save them disregard this principle and lose sight of the Mediator, Jesus Christ. True Christian theology does not inquire into the nature of God, but into God's purpose and will in Christ, whom God incorporated in our flesh to live and to die for our sins. There is nothing more dangerous than to speculate about the incomprehensible power, wisdom, and majesty of God when the conscience is in turmoil over sin. To do so is to lose God altogether because God becomes intolerable when we seek to measure and to comprehend His infinite majesty.

We are to seek God as Paul tells us in I Corinthians 1:23, 24: We preach Christ crucified, unto the Jews a stumbling block, and unto the Greeks foolishness; but unto them which are called, both Jews and Greeks, Christ the power of God, and the wisdom of God." Begin with Christ. He came down to earth, lived among men, suffered, was crucified, and then He died, standing clearly before us, so that our hearts and eyes may fasten upon Him. Thus we shall be kept from climbing into heaven in a curious and futile search after the nature of God. If you ask how God may be found, who justifies sinners, know that there is no other God besides this man Christ
Jesus. Embrace Him, and forget about the nature of God. But these fanatics who exclude our Mediator in their dealings with God, do not believe me. Did not Christ Himself say: "I am the way, and the truth, and the life: no man cometh unto the Father, but by me"? Without Christ there is no access to the Father, but futile rambling; no truth, but hypocrisy; no life, but eternal death.

When you argue about the nature of God apart from the question of justification, you may be as profound as you like. But when you deal with conscience and with righteousness over against the law, sin, death, and the devil, you must close your mind to all inquiries into the nature of God, and concentrate upon Jesus Christ, who says, "Come unto me, all ye that labor and are heavy laden, and I will give you rest." Doing this, you will recognize the power, and majesty condescending to your condition according to Paul's statement to the Colossians, "In Christ are hid all the treasures of wisdom and knowledge," and, "In him dwelleth all the fulness of the Godhead bodily." Paul in wishing grace and peace not alone from God the Father, but also from Jesus Christ, wants to warn us against the curious incursions into the nature of God. We are to hear Christ, who has been appointed by the Father as our divine Teacher.

~Martin Luther, Commentary on Galatians 1:3.