But the devil places many obstacles in our way to keep us from understanding all this. Even after we do understand it, the devil is still reluctant to leave us undisturbed. He sends us physical and spiritual temptations—physical ones, to make us greedy, unchaste, and sensual; spiritual ones, to make us frivolous and indifferent to the words of God that are addressed to us in Baptism, in Holy Communion, and in absolution. Is it not despicable for anyone to be indifferent to words like “I baptize you” or “Whoever believes and is baptized” or “I forgive you your sins” or “Christ gives us His body and blood in the Lord’s Supper”? Therefore the wiseacres and schismatic spirits take offense at these words and despise them, as the proclamation of the Gospel is also despised because the persons who preach the Gospel are such insignificant men. These smart alecks suppose: “God really should present something more imposing!” Because of its plainness they also despise Baptism, while they boast and talk much about the Spirit.
But we must know that God carries out His work and accomplishes great things through this humble form of Word and Sacraments. He is trustworthy; He who testifies here cannot deceive us, for He is not a man who can lie. Neither is it a man who preaches and baptizes; it is God. And if God declares: “I want to save you by the Word,” you are to believe it; for by presenting His Word and Sacraments to us God deals graciously with us. He could pull a great whale from the ocean with a human hair—something we would be unable to do with many thousands of ropes. Therefore we should remember who this great Person is that deals with us in the Sacrament and addresses us through the office of the ministry. In six days He created heaven and earth. What sort of hands did He have for this task? Certainly not my fingers!
Therefore we should hold His voice, testimony, and statements in high esteem. They are so simple that we can cleave to them; God deals with us this way that we may be able to bear His presence. For if He were to come to deal with us in His true person and majesty, we would be lost. No one would believe it if He were to utter a word strong enough to resound from heaven to earth. No one would be able to endure a voice as great and powerful as the one on Mt. Sinai, when He spoke with trumpet blasts amid a great display of thunder, with the entire mountain on fire and enveloped in smoke, as is recorded in Ex. 19 and 20. The Israelites did not want to come before God; they asked Moses to be their spokesman that they might not all die. Moses said: “You are right. And God will give you another Prophet to whom you should cling (Deut. 18:15), that is, Christ. God will put His words into this Prophet’s mouth, and He will speak graciously to us.” But what happened on Mt. Sinai? There we could not endure God’s voice, and we complained that we would have to die if we had to listen to God. Therefore Christ was to speak so plainly and gently to us that we might believe His words and testimony and cling to them. When God had appeared in His majesty, it was altogether too frightful; but now that He has come in a humbler form, we want nothing of that either. Thus we do not want the proclamation of the Law because of its splendor and luster, while we despise this other proclamation as an insignificant and inconsequential matter.

Luther, M. (1999, c1957). Vol. 22: Luther’s works, vol. 22 : Sermons on the Gospel of St. John: Chapters 1-4 (J. J. Pelikan, H. C. Oswald & H. T. Lehmann, Ed.). Luther’s Works (22:vii-309). Saint Louis: Concordia Publishing House.