"Our English word Mediator is quite broad enough to cover the work done by our Redeemer for the Church; but that the Scriptural usage of the word Mediator confines it to a mediator of a Covenant. Hence, to be in accord with the Scriptural usage we will do wisely to use the word Mediator in the same restricted sense – only in connection with a Covenant. It is wise for us to use the Bible term Advocate when referring to our Lord's work for the Church. See the 'Watch Tower' April 1, '09, page 106, column 2, paragraph 3."
Again we repeat that the usage of a word in the Bible should guide us in our use of it. If the word Mediator were loosely used in the Bible in respect to any and all kinds of service between God and the Church, then we, too, might so use it. But as soon as we find out that it is not so used, we should desist from such a use of it and use it only in harmony with the Biblical usage. This is why we no longer use the word Mediator in respect to our Lord's various and valuable services for the Church, and refer to him as the Bible does – as "the Mediator of the New (Law) Covenant," but as our "Advocate with the Father."
That New (Law) Covenant is for natural Israel and the remainder of the world, and not for the Church of this Gospel Age, which Church is the Body of Christ, the Body of the great King, Mediator, Judge and Priest.
Only one text containing the word Mediator could be in doubt, and it only until the right interpretation is suggested. The text is – "There is one God and one mediator between God and men, the man Christ Jesus, who gave himself a ransom for all, to be testified in due time." – 1 Tim. 2:5,6.
The Apostle does not here refer to the Church, but to the world. Of the Church Jesus said, "Ye are not of the world, even as I am not of the world." The Apostle tells us that Jesus is the Mediator between God and the world – men. He is not mediating now, but, as the Mediator is getting ready to deal with the world in the Father's stead. He is now performing the sacrifice of atonement – accepting the willing offerings of believers and counting their sufferings as his own, even unto death. Shortly, with these his members, added, this great Mediator will present the blood which will seal the New (Law) Covenant. And then the blessing of Israel and all the nations by restitution opportunities will begin. Note the context. The Apostle is not discussing the Church, but the world – "kings and all in authority."
When did our Lord become the Mediator of the New (Law) Covenant or a mediator in any sense? Not when he was born the babe of Bethlehem! Not when baptized at Jordan! but when he had sacrificed to the finish and was raised from the dead to be a Prince and a Savior, as the Head of the Spiritual Seed of Abraham. That entire Seed will be the Mediator when all the sacrificing will be finished and the entire Church glorified.
But look again! In the Old Testament this "Messenger of the Covenant" is mentioned in Malachi 3:1. And the mention of a New (Law) Covenant in Jeremiah 31:31 implies a mediator for it. Nevertheless the scroll of Divine purpose was still sealed and in the hand of Jehovah, up to the time that the Lamb had been slain. Not until after he was slain was it proclaimed, Worthy is the Lamb that was slain to receive glory and honor, etc., and the scroll. – Rev. 5:1-12.
The explanation is that God prophetically foretold that he would find one worthy of this great honor of being Abraham's Seed and Mediator of the New (Law) Covenant. However, it was left to our Lord still to demonstrate his worthiness to be that one – that Mediator. Nor was his trial a mere farce! He was in an agony in Gethsemane lest he had failed to make his calling and election sure. Do we not read, "He offered up strong crying and tears unto him who was able to save him out of death, and was heard in regard to the thing which he feared"? (Heb. 5:7.) And is it not the same with his members – the members of the Mediator? He who foreknew Jesus foreknew us also by Jesus. Were we not "chosen in him from before the foundation of the world"? Hence the exhortation to us, also, to make our calling and election sure. [R4438 : page 220]
Nor does the Church need either a mediator or a Covenant for her justification. She is justified by faith, not by works of the Law either under the Old Law Covenant or under the New (Law) Covenant. As it is written, "Abraham was justified by faith" – and so were all the Ancient Worthies, of whom it is written, "They had this testimony, that they pleased God." This testimony to their justification was given long before Jesus was born. And similarly, before Jesus died, he testified, "The Father himself loveth you." If God loves us and we love God, what need is there for a mediator between lovers? See how we were justified. – Rom. 4:22-24; Gal. 3:14.
Let us settle the matter in our hearts that our call is to become members of the Mediator between God and the world – the antitype of Moses, the mediator of the Law Covenant. This antitypical Moses has been in process of raising up for nearly nineteen centuries. (Acts 3:22,23.) Our Redeemer's death is the "surety" for us, his members, and for the New (Law) Covenant. – Heb. 7:22.