The Jewish religion was validly established by God. But in the fullness of time, the Old Covenant wore out:
In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
And therefore, the Jews were expected to transfer their allegiance, so to speak, from Moses to Jesus:
Romans 7:2For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband.
3So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man.
4Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God.
But many of them did not do so. They are not, in my opinion, therefore condemned:
Acts 10:33Immediately therefore I sent to thee; and thou hast well done that thou art come. Now therefore are we all here present before God, to hear all things that are commanded thee of God.
34Then Peter opened his mouth, and said, Of a truth I perceive that God is no respecter of persons:
35But in every nation he that feareth him, and worketh righteousness, is accepted with him.
And although the Old Covenant is fading away, the Law of the Commandments remains the foundation of our joint faiths:
Revelation 22:14Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
What advantage then is the Christian’s?
Romans 3:1What advantage then hath the Jew? or what profit is there of circumcision? 2Much every way: chiefly, because that unto them were committed the oracles of God.
3For what if some did not believe? shall their unbelief make the faith of God without effect?
Yes, it is true that the Jews were first committed the Scriptures and the Word of God. However, in the New Covenant, we are given the Sacraments. Justification by faith without works. We are entitled, by God, to enter heaven itself, being members of the Body of Christ:
Matthew 11:11Verily I say unto you, Among them that are born of women there hath not risen a greater than John the Baptist: notwithstanding he that is least in the kingdom of heaven is greater than he.
That, in a nutshell, is the GOOD NEWS. We, being baptized, become children of God and walk with the Saints of God:
Hebrews 12:22But ye are come unto mount Sion, and unto the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels,
23To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,
24And to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel.
Whereas they, the Jews and all other religions, have to await the Final Judgment before they will be permitted into the Kingdom, if God so wills.
…here we have two things at work… the exact method of man’s Salvation is in deed Christ since there’s no other name on earth and in Heaven by which man can gain Salvation… hence, Christians are not to muddy-down the Faith in the erroneous belief that by rejecting Christ or diluting the Faith we can help save those who reject Christ as their Lord and Savior…
…then there’s God’s Mercy and Love which only God can Dispense… He will be the Final and Only Judge that would be able to determine if a person rejected Christ willfully or if by ignorance that person has not come to Know Jesus.
Regardless upon the case, Salvation and Conviction is a matter of the Holy Spirit and not ours!
Our job/function is to be Christ’s Witnesses and to Stand for Him!