(1) Please explain Heb. 9:15, viz., Revised Version – "And for this cause he is the mediator of a New Covenant, that a death having taken place for the redemption of the transgressions that were under the first Covenant, they that have been called may receive the promise of the eternal inheritance."
(1) This text shows a contrast between the old Law Covenant and the New [Law] Covenant. The original or Abrahamic Covenant, under which Christ and his Body as the Spiritual Seed of Abraham is being developed, is not in the discussion. The Apostle wrote to those who still trusted in the Law Covenant and declared that it was necessary, not only to believe in Christ, but also to keep the Law and to be circumcised, in order to have any Divine favor. This the Apostle is controverting as untrue. He shows that the Law Covenant mediated by Moses was typical of a superior New Covenant, of which Messiah is the Mediator.
Moses' Covenant was already dead, to the extent that the prize it offered had been won by Jesus. It is still alive, however, upon all the Jews as a bondage from which they could get free only in one of two ways; either by dying to the Law Covenant and to all of its hopes and prospects and renouncing all earthly restitution rights and thus becoming a joint-heir with Christ as a member of Messiah's Body during this Gospel Age; or, accepting the other alternative, get free from the old Law Covenant by transfer, when the New [Law] Covenant shall go into effect as its substitute, at the beginning of the Millennium. Then all Jews and their appurtenances will be transferred from Moses, the incompetent mediator, to the Messiah of glory, the competent Mediator of the better Covenant, whose provisions will bless Israel and all the families of the earth willing to come in under its benevolent provisions.
This text has no reference to any except Jews who were under the old Law Covenant. It does not at all refer to Gentiles. It shows that God's provision is that Messiah is the Mediator of Israel's New Covenant and that his death, when so applied, will be sufficient to cancel the transgressions of Israel under their old Law Covenant. This will make it possible for them as a nation yet to attain the earthly part of the Abrahamic Covenant's provision for Abraham's earthly seed, as the sand of the sea shore. Thus eventually Israel as God's "called" nation will receive all that they ever expected – and more. Israel's promises were not heavenly or spiritual, but earthly: "All the land that thou seest to thee (Abraham) will I give it, and to thy seed after thee"; and as the chief nation of earth they were to teach all nations "every man under his own vine and fig tree."
Those promises are sure as God's word. They merely wait until the "Mystery" of a multitudinous Mediator shall be finished (in sacrifice and in resurrection glory). Then the "Mystery" Mediator will have sealed Israel's New Covenant by his death as its Testator. Then the "called" nation of Israel will "receive the eternal inheritance" for which they have waited more than thirty-five centuries. St. Paul explains this further in Romans 11:27-29,31.
(2) As elsewhere shown, our Lord's sacrifice did not pay for the sins of the world, but did provide the ransom price which he will later present to Justice on behalf of the sins of the world.
(3) Your argument is not logical. If our Lord had finished his work of sacrifice he could not give his footstep followers a share therein.
(4) The Scriptures nowhere say that our Lord sealed the New Covenant with his blood. Neither was it necessary for him to seal the New Covenant before he would be its Mediator. He was the Mediator of the New Covenant in the Divine purpose and promise centuries before he became the man Christ Jesus. He was the Mediator of the New Covenant when born in Bethlehem in exactly the same sense that he was then the Savior of the world: not because he had sealed the New Covenant nor because he had saved the world, but because he was the One through whom the world's salvation and the New Covenant for its blessing were eventually to be accomplished.
Our Lord has not yet saved the world, nor has he acted as the Mediator of the New Covenant; but he will accomplish both purposes during the Millennial Age; and at its conclusion the prophecy will be fulfilled, "He shall see of the travail of his soul and shall be satisfied." Our Lord was privileged to offer his Church a share with himself in his Mediatorial Kingdom on condition that she would share in his cup of suffering and self-sacrifice – share in his baptism into his death. So doing she shall share his reward of glory, honor and immortality in "his resurrection." (Phil. 3:10.) And sharing his glory and throne as his joint-sacrificer and joint-heir of the promise she would be with him jointly the Mediator between God and men – the world – during the Millennial Age – the work of reconciling the world, or so many of them as may prove willing to receive the blessing of regeneration.
(5) You are not right. There is a difference between a covenant and the law of a covenant. God's Law given to Israel summarized was, "Thou shalt love the Lord thy God with all thy heart, with all thy mind, with all thy being and with all thy strength; and thou shalt love thy neighbor as thyself." That Law is perfect and will be the basis or Law of the New Covenant. Moses as a Mediator under his Covenant purposed to help Israel to keep that Law, and God covenanted to give them eternal life, if they would do so. But they were unable to keep that Law perfectly in act and thought and word, and hence they reaped its condemnation of death and not its proffered blessing of life. Under that Covenant Moses was privileged to arrange sacrifices and offerings for sin, and thus year by year to cleanse the people for a year at a time from their original condemnation. But he had no means of actually blotting out their sins and no power or right to actually restore them to perfection and ability to keep that Law.
The New Covenant will have the same Law exactly, but the Mediator having by then paid over to Justice the ransom-price of the world, secured by his own sacrificial death, will then have full charge of mankind and be fully empowered to deal mercifully with their imperfections and to help them step by step out of their sin and death condition back to perfection, and to cut off the rebellious in the Second Death. At the close of the Millennium he will present the willing and obedient to the Father actually perfect.
Thus it will be seen that God's dealings with mankind under the typical Law Covenant, and under its antitype the New Covenant, is along the lines of actual obedience to the Divine Law, and not along the lines of reckoned obedience through faith. As obedience to the old Law Covenant held the reward of human perfection and life, so the rewards of the New [Law] Covenant will be similar – eternal life or eternal death.
Quite to the contrary of both of these arrangements, the Church is now called to a "heavenly calling" under the Abrahamic Covenant – to be members of the Body of Christ, who, with Jesus her Head, will constitute the Mediator of the New Covenant. The Church is "not under Law, but under grace," not judged according to the flesh and earthly restitution, but judged according to the heart and intention; and required to sacrifice restitution rights to the attainment of "the high calling" life and glory on the spirit plane as members of the Mediator of the New Covenant.
(6) Please explain John 13:34 – "A new commandment I give unto you, that ye love one another." Was it a forerunner of the New Covenant he was about to seal for them?
(6) No, that "New Commandment" represents a higher law than was given to the Jew under the Law Covenant, hence higher also than will be given to Israel and mankind under the New Covenant. The New Commandment mentioned by our Lord is not the Father's commandment at all, but the command of our Head, our Teacher, to all those who have entered the School of Christ and who are hoping to become "members" of the Anointed One – members of the Mediator, Prophet, Priest and King of the new dispensation. Justice could not give this new command: all that Justice could command is expressed in the Law given to Israel, namely, supreme love for God and love for the neighbor as for one's self. This new commandment which the Lord gave applies only to the Church of this Gospel Age. In effect it is this: If you would be my disciples, if you would share my throne and glory and immortality, you must have my spirit. You must do more than keep the Law. You must be more than just. You must be self-sacrificing. If you would share my glory I command and direct that you love one another as I have loved you. (John 15:12.) I have loved you to the extent of laying down my life for you sacrificially. You must have this same spirit and cast in your lot with me in self-sacrifice, or you cannot be my disciples, nor share my glory, and associate in my work as the Mediator for the blessing of Israel and mankind. Whosoever will be my disciple must take up his cross and follow me, that where I am there shall my disciple be. Surely no one can doubt the Savior's meaning – my disciples must die with me.