Defining Messiah
First, let’s establish what a “Messiah” is according to the Tanach
Messiah – Moshiach in Hebrew – means “anointed one” and is a term used to refer to anointing certain people in the Tanach – such as the kings and priests
If the anointed kohen sins, bringing guilt to the people, then he shall bring for his sin which he has committed, an unblemished young bull as a sin offering to the Lord. (Leviticus 4:3)
The word Messiah can also refer to holy objects that are consecrated
You shall take the anointing oil and anoint the Mishkan and everything within it, and you shall sanctify it and all its furnishings; thus it will become a holy thing. (Exodus 40:9)
The root word is “mashach” which means to smear, anoint, or consecrate
And Samuel took the horn of oil, and anointed him in the midst of his brothers. And a spirit of the Lord passed over David from that day forth, and Samuel arose and went to Ramah. (I Samuel 16:13)
When most people refer to the “Messiah” they are referring to the End Time Messiah
The Talmud (in Sanhedrin 98a-99a) has a long discussion about the Messiah and the Messianic Age
One of the first things discussed by the sages was the fact that until Israel repents, the Messiah will not arrive
Rabbi Eliezer said to him: But isn’t it already stated: “If you will return, Israel, says the Lord, return to Me” (Jeremiah 4:1), indicating that redemption is contingent upon repentance? (Sanhedrin 98a)
However, there is also a belief that the time of redemption is set and not dependent upon repentance.
Rabbi Yehoshua said to him: But isn’t it already stated: “And I heard the man clothed in linen, who was above the waters of the river, when he lifted up his right hand and his left hand to heaven and swore by the One Who lives forever that it shall be for a period, periods, and a half; when the crushing of the power of the holy people shall have been completed, all these things shall be finished” (Daniel 12:7), indicating that the time for redemption is set and unrelated to repentance? (Sanhedrin 98a)
Maimonides write in his Mishneh Torah:
In the future, the Messianic king will arise and renew the Davidic dynasty, restoring it to its initial sovereignty. He will build the Temple and gather the dispersed of Israel.
Then, in his days, the observance of all the statutes will return to their previous state. We will offer sacrifices, observe the Sabbatical and Jubilee years according to all their particulars as described by the Torah.
Anyone who does not believe in him or does not await his coming, denies not only the statements of the other prophets, but those of the Torah and Moses, our teacher. The Torah testified to his coming, as Deuteronomy 30:3-5 states:
God will bring back your captivity and have mercy upon you. He will again gather you from among the nations… Even if your Diaspora is at the ends of the heavens, God will gather you up from there… and bring you to the land….
These explicit words of the Torah include all the statements made by all the prophets. (MT Kings and Wars 11:1)
Two Messiahs
I just want to briefly touch upon the idea within Judaism about two End Time Messiah figures – Messiah ben David and Messiah ben Joseph – before Christians start harping about this issue in the comments
This is not a firm belief in Judaism and not all Jews accept that there will be such a person as Messiah ben-Joseph.
Apropos the eulogy at the end of days, the Gemara asks: For what is the nature of this eulogy? The Gemara answers: Rabbi Dosa and the Rabbis disagree concerning this matter. One said that this eulogy is for Messiah ben Yosef who was killed in the war of Gog from the land of Magog prior to the ultimate redemption with the coming of Messiah ben David. And one said that this eulogy is for the evil inclination that was killed. (Sukkah 52a)
The reasoning is that this is the mourning referred to in Zechariah 12:10. This national mourning will lead to the entire nation of Israel to repentance and this will lead to the revelation of Messiah ben-David – that is, the end-time Messiah who will be an earthly king.
Once the Messiah ben David saw Messiah ben Yosef, who was killed, he says to the Holy One, Blessed be He: Master of the Universe, I ask of you only life; that I will not suffer the same fate. The Holy One, Blessed be He, says to him: Life? Even before you stated this request, your father, David, already prophesied about you with regard to this matter precisely, as it is stated: “He asked life of You, You gave it to him; even length of days for ever and ever” (Psalms 21:5). (Sukkah 52a)
Rambam doesn’t even list the concept of Mesiah ben-Joseph in his Mishneh Torah. Meaning, while he may have believed that there might be such a person at the end times, it is not a requirement.
Ultimately, Messiah ben Joseph (if he will indeed exist) will act as a precursor to Messiah ben-David. Messiah ben Jospeh will NOT be a descendant of David and will NOT act as king. He will be a political and military leader.