1. It is a wrong thought to think of the "Mediator" as acting between God and the sinners as individuals. Let us hold tight to the Scriptural proposition that a Mediator has to do only with a Covenant and that the Covenant deals with a nation of people and not with its individuals. God will not make New Covenants with each member of Adam's race and have Messiah mediate billions of Covenants. The correct thought is very different. When the great High Priest shall have finished His offerings, first for His own members and His house, and then for all the people, He will present the merit of His sacrifice on the world's behalf, redeeming the World (according to the original intention), as more than nineteen centuries ago, He redeemed or bought the Church, the household of faith. R4555:(?); R5690, 5691
2. He will Mediate for Israel the New Covenant as a substitute for their old one, restoring Israel to the place of honor as the favored nation, Abraham's natural seed, through whom the blessings of redemption will extend to all nations. That New Covenant will not be made with rebellious sinners, however. God's Covenant will be with the Mediator for Israel, guaranteeing forgiveness and reconciliation to all of Abraham's natural seed who will exercise the faith and the obedience of Abraham. The work of the Mediator with Israel (and the world of mankind, who to be blessed must become Israelites indeed) during the Mediatorial reign, will be their instruction, enlightenment and uplifting out of sin and death, out of ignorance and superstition, out of depravity and unbelief up to human perfection; so that at the end of the Millennium, all of Abraham's seed, all of his faith and obedience, will have reached human perfection and be ready for the Mediator to deliver them over to the Father, that God may be all in all--the unwilling and rebellious, after due trial, being cut off during the reign in the second death. R4555:2; FF:3
3. The Mediator of "many members" has been in process of development during this whole Gospel age, and the "better sacrifices" as the basis for the New Covenant have been in process of offering. Jesus has not exercised His office as Mediator for the world; and the world has no relationship with God, but still lies in the wicked one. God raised up Jesus first and since has been raising up the Church, and soon will finish the raising up. It is this Mediator or Prophet of whom St. Peter speaks in Acts 3:22,23. See also 1Tim.2:5,6. No mediating can be done until the Mediator of "many members" has qualified for the office. His qualification consists of his sacrifice, according to his Covenant of Sacrifice. The Christ, Head and Body, are, therefore, the Mediator for the World in a prospective sense-- in the same sense as Jesus, the Babe, could be spoken of as the Savior and the King. He is only now becoming the King and has yet saved only a few of His people(his Church). R5928:2; FF:3,4; Rev.22:17
4. The work of an Advocate is different, and according to the Bible, relates only to the work which Jesus accomplishes on behalf of the Church during this age. The Church will need no Advocate in the future. The World has no Advocate now. "We have an Advocate with the Father, Jesus Christ, the Righteous", 1John 2:1. It is Jesus individually who is the Advocate for us--"the Church, His body." He advocates our cause--first of all by imputing to us the merit of His sacrifice, thus making us presentable as sons of God. Because of this Advocacy, we have received the holy Spirit and are New Creatures in Christ. As New Creatures we still need our Advocate, because we cannot do the things that we would--perfectly. We have imperfections of the flesh which, as New Creatures, we cannot fully control. Hence we need a throne of grace and an Advocate through whom we may maintain our present relationship with the Father, and thus not be condemned with the world. R5928:8; R5197; Rom.12:5; 1Cor.12:27; Ephes.5:30; Col.1:18