“For there is one God and one mediator between God and man — the man Jesus Christ who gave himself as a ransom for all — the testimony of a unique appointed time.”
(1 Timothy 2:5-6)
So, is there salvation outside of Christ? No. It is a logical impossibility. No human can do it because humans are sinful and no animal can do it on our behalf. Only God is capable of interceding for a fallen man and so to do just that, God took on flesh — Jesus the Christ. To mediate for others, you must also be able to identify with those for whom you mediate (hence Abraham could not effectively mediate for Sodom — see Genesis 18:22-33).
The one who mediates between God and man must be both fully God and fully man. He must be powerful enough to take on the penalty of man and thus be God, but must be able to suffer and die as a man, meaning he must be man. It is the great and the only solution to our weak and fallen condition. Nothing else will satisfy the demands of the law. Moses could not do it, Abraham could not do it, Buddha could not do it, Mohammed could not do it, Joseph Smith could not do it, none other than Jesus the Christ could do it. And he did it for all sorts of people — for all who come to Christ in faith and repentance.
Notice something about the Apostle Paul’s words above. This is the testimony for Christians, but it was given at a distinct and unique appointed time. Such is a reminder that Christianity is a historical faith…were the events recorded within somehow not to have happened, the whole of our theology as Christian would be for naught. That testimony was in time and space and such must never be compromised by the church.