After Jesus prevailed over the devil in the wilderness, He returned in the Power of the Spirit. Henceforth He bore witness to the Father in Heaven by proclaiming words and performing works that corresponded to that Kingdom.
He said, If I cast out demons by the finger of God, then surely the Kingdom of Heaven has come upon (among) you.
To Jesus, declaring a Kingdom without displaying the substance and superior power of that Kingdom would fall into the realm of the ridiculous. Consider the response of the prophets of Baal, when God sent fire to consume the alter at Mt. Carmel in answer to Elijah’s prayer of faith:
When all the people saw it, they fell on their faces; and they said, “ The Lord, He is God; the Lord, He is God.” 1 Kings 18:39
What do you imagine would have transpired if God withheld the fire? Elijah would have been torn to pieces.
At some level the full Gospel is always confrontational. It must create a new person. It must destroy the works of darkness. The Gospel of Jesus Christ must do.
Jesus takes this to the limit. He flat out tells everyone not to believe Him, if He does not back up His words with the miraculous power that comes from the very Kingdom He proclaims.
If I do not do the works of My Father, do not believe Me; but if I do them, though you do not believe Me, believe the works, so that you may know and understand that the Father is in Me, and I in the Father. John 10:37-39
It is completely reasonable, then, that Jesus would command His disciples to wait in Jerusalem to be clothed with heavenly power so they might appropriately testify and bear witness to His Name and His Lordship. As the Father did not, would not, send Jesus to reveal His Name without the powers of the Heavenly Kingdom, so Jesus would not send His disciples to reveal His Name with mere words.
Would it not be perfectly appropriate for any of us who might actually stand and declare the Gospel as the Lord commanded us, to say:
“I declare to you today the glories and wonders of the Kingdom of Jesus Christ. If I do not back it up with manifestations of the power of His Kingdom, just ignore me and go home. I would not be bearing witness to Christ as He is. Persuading you with words while omitting the power is not the same Kingdom that Jesus proclaimed.”
Every day people are assailed by hustlers selling widgets that do not widge. The world has every right to dismiss us flat out if our witness of Christ consists of words and omits His power. Our supreme Lord Himself refused to hold liable men who disbelieved His words if not accompanied by His miraculous works. Is the servant greater than his Master?