When Jesus Christ was on earth, He preached the gospel of the Kingdom of God (Matthew 4:23; 9:35; Mark 1:14-15). However, something foundational happened before He began preaching the gospel and performing the various miracles that showed He was from God. Something essential happened before He could preach and perform works as a man. We can find what this was in John 10:36-38:
. . . do you say of Him whom the Father sanctified and sent into the world, "You are blaspheming," because I said, "I am the Son of God"? If I do not do the works of My Father, do not believe Me; but if I do, though you do not believe Me, believe the works, that you may know and believe that the Father is in Me, and I in Him.
The key element appears in verse 36. Jesus says that He was sanctified before He was sent into the world. He was set apart in order to do all that He did, and that certainly includes the preaching of the gospel. His three-and-a-half-year ministry was the result of the sanctifying done by the Father.
The gospel accounts are overflowing with statements by Christ that show that all of His words and actions had their source in the Father. His preaching of the gospel is no exception. The content of His message and the power to proclaim it both came from the Father.
Jesus testifies in Luke 4:18 that He was "anointed" to preach the gospel to the poor, another way of saying that He was set apart. He says that He could do nothing of Himself, but only what He saw the Father do (John 5:19, 30). He declares that the works He did bore witness that the Father had sent Him, meaning He was being directed by the Father (John 5:36-37; 8:18). He asserts that He could do nothing of Himself, but He could speak only as the Father taught Him and of what He had seen while He was with the Father (John 8:28, 38). He states that He did not speak on His own authority, but that the Father commanded Him in what He should speak (John 12:49).
John the Baptist demonstrates this same principle when saying, "A man can receive nothing unless it has been given to him from heaven" (John 3:27).
All of these statements set the stage for understanding Christ's preaching. When Jesus went about preaching the gospel, saying, "The time is fulfilled, and the kingdom of God is at hand. Repent, and believe in the gospel" (Mark 1:14-15), the only reason it had any effect is because He had been sanctified—set apart—by the Father to do this.
When Jesus said that it was the Father who was actually doing the works, the preaching of the gospel was one of them (John 10:32; 14:10). This means that, regardless of what human instrument God uses or what method He employs, the reality is that it is God who preaches the gospel! If He is not the Source of everything, as He was for Jesus, then it is a work of man and not of God, and "the weary workers toil in vain" (Psalm 127:1, paraphrase).
It actually does not take anything miraculous to know what the true gospel is or to speak the words. In fact, when Jesus sent the disciples out to preach the gospel, they did not even have the Holy Spirit! They were not even really converted yet, though they had been called. Even so, if something is going to be accomplished, it will be as a result of God's sanctification, which the disciples had. That is the consistent biblical pattern.
The bottom line, then, is that the gospel is not preached through human effort or human will. It is proclaimed through submission to God's leadership. If submission to God is absent, the works that God desires will not be produced. If men go outside God's will—however well-intentioned they may be—their words, to borrow from Shakespeare, may as well be the proverbial "tale, told by an idiot, full of sound and fury, signifying nothing."