Over the past 2,000 years a vast sea of literature has developed in traditional Judaism, starting with the Mishna (codified in the early 3rd century AD) and the Gemara (mid 5th century AD). (Note: The New Covenant was written by the end of the 1st century AD - which means that it far precedes these talmudic writings.)
Since the rabbinic literature is so vast and diverse, we should avoid over-simplistic evaluations. However, there is a need to summarize a basic approach in as simple terms as possible. Here is my view:
1. Scriptures - The Tenach (Hebrew scriptures: Law, Prophets and Writings) and the New Covenant (Gospels and Epistles) are the only authorized and inspired standard of truth.
2. Religious Literature - All other literature both in Jewish and Christian traditions have varying degrees of truth, some much more and some much less. They can all be studied for educational purposes, as long as there is a discerning eye to receive the good and reject the bad.
3. Three Streams - Three streams of interpretations during the period of the Tenach stand out: 1) a mixture of faith with the surrounding pagan culture; 2) a ritualism which turned the covenant symbols into the focus of worship; 3) a spiritual-moral view including Messianic prophecies. We believe the third to be the correct one, and its interpretation is reflected in the New Covenant.
The pagan mixture can be seen in the gentile culture imported into Israel during the Assyrian captivity (II Kings 17:41). Religious ritualism can be seen in the idolizing of the Bronze Serpent (Nechushtan), removed by Hezekiah (II Kings 18:4). These two types of errors can be found in various streams of Judaism and Christianity today.
The spiritual view can be seen in Moses' cry for heart circumcision (Deut. 30:6), Isaiah's for Torah in the heart (Isa. 51:7), Jeremiah's for a new covenant (Jer. 31:31), and Ezekiel's for a new spirit (Ezek. 36:26). This stream of interpretation came into its fullness in the teachings of Yeshua. He universalized the commandment to love our neighbor (Lev. 19) in His teaching about the Good Samaritan (Luke 10). He taught that loving-kindness is more important in Torah than religious rituals (Mark 12).
4. Ritual Law (Halacha) - Halacha standardizes the customs and rituals of Judaism. By the sovereign hand of God, much of the halacha points to Yeshua even though the majority of those who observe it do not believe in Him (the Passover seder, the Mikveh waters, the Hanukah menorah, etc.). Yeshua affirmed rabbinic authority as a continuation of the Levitical priesthood saying the Pharisees "sit in the seat of Moses" (Matt. 23:3). On the other hand, Yeshua sharply criticized the Pharisees for their hypocrisy and warned us against their interpretations (Matthew 23:4-33). The fundamental concept of religious ritualism is mistaken. The over-emphasis on hand washing, head coverings, separating dishes, candle lighting, etc. misses the very purpose for which the Law and the Prophets were given.
5. Mysticism (Kabbalah) - Kabbalah contains spirituality and symbolism similar to the book of Revelation. However, involvement in mystic experiences without the lordship of Yeshua (I John 4:2), and without clear Scriptural guidelines can lead to occultism, cultism and spiritual delusion. For this reason, Kabbalah is even criticized within other streams of Judaism today.
6. Bible Commentaries - Rabbinic commentaries can be helpful in understanding the Hebrew texts and historical context of the Bible. In rabbinic literature we see concepts such as a Messianic king, the history of the Jewish people, linguistic word analysis and the covenants of Israel, which are often missing from Christian material. On the other hand, Jewish commentaries (including Rashi) were written long after the 1st century, many either purposely or subconsciously in a reaction against faith in Yeshua. For example, the texts of the suffering Messiah are said to refer to Israel as a people; Appearances of YHWH in the form of a man are dismissed; a positive destiny of the Gentile nations is downplayed, etc.
7. Balance - In summary, there are positive elements in rabbinic literature because of its faith in the covenants of our forefathers. If we neglect rabbinic literature altogether, we could miss key Jewish insights on the kingdom of God, which have been lost to Christianity due to religious pride and prejudice. On the other hand, the rejection of Yeshua in rabbinic writings has hindered millions of our dear relatives from finding atonement and eternal life in Yeshua (Rom. 11:28). Lack of caution about the anti-Yeshua spirit in rabbinic literature has also led to some confusion, unbelief and religiosity in Messianic Judaism.
[End note: My studies of rabbinic literature include a Masters Degree from Baltimore Hebrew University and several years of classes with ultra-orthodox rabbis in Jerusalem. However, as I have made it my priority to preach the Gospel and teach the Bible, my expertise in rabbinic material is by necessity limited.]