My previous two posts (here and here) lay the foundation that 'new life' is an ancient doctrine re-taught by Christ and early Christians rather than invented by them at that time. Joseph Smith learned this through revelation. 'New life' doctrine is taught numerous times in the Book of Mormon. We also find it in the Book of Moses, where Adam is taught the purpose of the Gospel:
59 That by reason of transgression cometh the fall, which fall bringeth death, and inasmuch as ye were born into the world by water, and blood, and the spirit, which I have made, and so became of dust a living soul, even so ye must be born again into the kingdom of heaven, of water, and of the Spirit, and be cleansed by blood, even the blood of mine Only Begotten; that ye might be sanctified from all sin, and enjoy the words of eternal life in this world, and eternal life in the world to come, even immortal glory; (Moses 6)
This is supported by archaeological discoveries which came later. I'll outline a few ancient examples below.
The Damascus Document
This is a Jewish text discovered relatively intact in 1897 and then found in fragments among the dead sea scrolls in the 1940s. This text is from the pre-Christian era and includes language that sounds surprisingly Christian, including talk of eternal life through God making atonement and "hidden things" revealed in connection to the covenant (also insinuating that all Israel had gone astray, perhaps by suppressing this teaching). For example:
But with them that held fast to the commandments of God, who were left among them, God confirmed His covenant with Israel for ever, revealing unto them the hidden things in which all Israel erred: His holy Sabbaths and His glorious festivals, the testimony of His righteousness and the ways of His truth and the desires of His will which a man shall do and live by them. He opened before them and they digged a well of many waters, and he that despises them shall not live. But they wallowed in the transgression of man and in the ways of the unclean woman. And they said that it belongs to us. But God in the abundance of His wonder made atonement for their sins and forgave their transgression. And He built them a sure house in Israel, the like of which never arose beforetime and hitherto. They who hold fast to Him are for the life of eternity, and all glory of man is for them; as God confirmed it to them through Ezekiel, the prophet, saying: "The priests and the Levites and the sons of Zadok that kept the charge of His sanctuary when the children of Israel went astray from them they shall bring near unto me fat and blood." (Damascus Document ch. 5, source here)
Notice the mention of the "sure house in Israel" connecting the concept of the Atonement for sin and eternal life. This is a clear reference to the temple, where those sin offerings were to be made according to the law of Moses to point the mind forward to Christ. For me, this is clear evidence that branches of Jews maintained the original understanding of their religion and looked forward to Christ who would come and make atonement for sin, leading them to eternal life.
Qumran Hymns
These hymns come from the same Jewish sect living in exile from Jerusalem in the centuries leading up to the time of Christ. Margaret Barker quotes the hymn known as QHXVIII: "Thou hast taught them thy marvelous mysteries ... that he may stand before thee with the everlasting host ... to be renewed with all the living and to rejoice together with them that know." Multiple hymns "tell of someone raised to the everlasting height to be part of the congregation of the sons of heaven." (The Great High Priest, p. 26-27)
Conclusion
History is written by the winners. This applies to doctrine as well. It is important when we look at truth claims of the restoration to be wary of assuming the mainstream view of a doctrine is the correct or original version of that doctrine. In light of the general human trend to drift from mantic to sophic, and in light of the evidence that indicates the original Israelite religion knew of the importance of the Messiah, we should be cautious in how we approach the topic.