During His farewell discourse, Yeshua prayed that we might be one in Him and in the Father:
I in them and You in Me, that they may be perfected in unity, so that the world may know that You sent Me, and loved them, even as You have loved Me. (John 17:23)
When He prayed this prayer, He had only the men with Him in the room. Since then, faith in Him has grown to encompass the world, a faith as broad and diverse as the earth itself. The world has believed and is continuing to come to believe that God has sent Messiah.
The Master’s prayers do not go unanswered.
He prayed that every disciple and every believer might be unified. What kind of oneness is this? The various beliefs and religious movements that have sprung from the Gospels have demonstrated anything but unity. Already by the second century, those who identified themselves as Christians fractured into sects, divisions, and heresies. The situation has scarcely improved since then.
The oneness of which the Master spoke was not collegial, theological, or ecumenical. He spoke of a spiritual connection caught up into the mystical unity He shared with the Father. That spiritual unity transcends the surface differences that separate and divide His true disciples. Just as the Father is in Messiah and Messiah is in the Father, so too, we are all joined together in a common bond with Father and Son by means of the Way, the Truth, and the Life, which is Messiah.
Sincere and God-fearing disciples of Yeshua often have vast differences in how they apprehend, understand, and explain truth. We differ in the way we formulate our creeds and practice our convictions, and for the most part, these differences are substantial. They are usually not insignificant issues that can be dismissed in favor of a vague ecumenicalism. Instead, they are substantial differences that often preclude the possibility of mutually edifying, peaceful fellowship.
Despite that, the Master commands us to endeavor to live out that spiritual unity in the flesh, in our relationships with one another. The disciples of Yeshua are to love one another with fierce devotion, as Yeshua loved them. Messianic Jewish pioneer Paul Philip Levertoff remarks:
The test of true love for Him is love for the brethren. This is His only commandment to His disciples: that those whom the Father has given Him should “all be one, as Thou Father are in Me and I in Thee” (John 17:11, 21-23). It is His ultimate and highest aim. He died in order “to gather together in one the children of God that were scattered abroad” (John 11:52). All His gifts to them—“the name of God,” His glory—have this end in view … this perfect achdut [“unity”] is founded on the oneness of Jesus with the Father. It is a reciprocal giving and receiving. This unity of the disciples will be the best proof to the world that God has sent Him (John 5:21). The world cannot awaken true love and unity among men, but it can recognize them. The world will know that “Thou lovedst them (the disciples) even as Thou lovedst Me.” (Love and the Messianic Age)
As God’s love enables Jesus to love, so does the love of Jesus enable them to love. As Jesus cannot work without God, so they cannot work without Jesus. As Jesus gives to them what God has given to Him, so they give to one another what Jesus has given to them. The love which He awakens in them consists in this willingness and ability to give. From this reciprocal giving and receiving, the fellowship’s unity is derived. (Love and the Messianic Age)