The majority of Christians assume that Mary, the mother of Jesus, was the daughter of Eli in the genealogy listed in the gospel of Luke and she was of the tribe of Judah. The reason that they believe this is because this is the explanation that their churches give them, which has been handed down through the centuries via the Catholic Church. However, Mary was of the tribe of Levi and not the daughter of Eli. The reasons Christians believe this this are the following:

1. First, because Jesus in order to qualify to be the Messiah, he had to be of royal lineage of the house of David (Judah).
2. Second, because the lineage in the gospel of Matthew is obviously that of Joseph, so it could only be the genealogy in Luke (so they think).
3. Third, because the church fathers needed to prove in some way that Jesus was God and the Messiah at the same time, so they came up with this theory (with no proof) that the lineage in Luke, though it seems to be that of Joseph, it is some how the lineage of Mary. This is most likely since they reason that Joseph couldn’t possibly have two lineages.

We are not talking here about some gray area in doctrine of the bible, this is black and white stuff that we have mostly as solid proof.

Mary’s cousin, Elisabeth and her husband Zachariah were Levites, which makes Mary a Levite.

The bible says so:

Luk 1:5 There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth.

So they were both of the tribe of Levi and not of Judah. So Mary was at least half Levite on this count, assuming that her mother was the sister of either Zachariah’s mother or father or Elisabeth’s mother or father.

If the relative of Zachariah and Elisabeth was Joachim then that would make Mary a full-blood Levite since priests only married women within the tribe of Levi. The prime example here being Zachariah who married Elisabeth a Levite woman.

Eli, the supposed father of Mary in the gospel of Luke died childless.

So Eli could not possibly be Mary’s father. This eliminates Mary from being of the lineage of Eli, thus she wasn’t of royal lineage.

And even if she had been the daughter of Eli, she would not have been able to give birth to the Messiah, since the Messiah’s lineage had to come through Solomon. Eli’s lineage was through Nathan, not Solomon.

Jesus’ flesh and blood relatives say that Eli was Joseph’s step father.

Jacob raised up seed to him, begetting Joseph, his own son by nature, but by law the son of Eli. Thus Joseph was the son of both.”

This explains why Joseph had a different lineage in both gospels, Matthew and Luke.

James, the flesh and blood brother of Jesus said Mary’s father was a priest of the name Joachim.

Mary herself was not of the tribe of Judah but of the tribe of Levi; her father being a priest of the name of Joachim . (http://www.orthodox.cn/patristics/apostolicfathers/mary.htm)

Mary was raised in the temple

Another thing that points to Mary being of the tribe of Levi was that she was raised in the temple. According to James, the brother of Jesus, Anna, her mother dedicated Mary to the Lord:

Jesus could only be a high priest if he were a descendant of Aaron, who would be of the tribe of Levi.

Another fact that points to Mary being of the tribe of Levi is the fact that Jesus, himself was a high priest of the order of Aaron which is recorded in the bible and as well as the Nazarenes:

Luk 4:16 And he came to Nazareth, where he had been brought up: and, as his custom was, he went into the synagogue on the sabbath day, and stood up for to read.

…and He taught there and in Jerusalem as an accepted Rabbi, even in the temple, none hindering Him. (GON 6.15)

Rabbi was a term used to address priests and Nathanael was a prominent leader of the Jews:

Joh 1:49 Nathanael answered and saith unto him, Rabbi, thou art the Son of God; thou art the King of Israel.

Even the epistle of Hebrews declares that Jesus was a high priest:

Heb 5:4 And no man taketh this honour unto himself, but he that is called of God, as was Aaron.

Heb 5:5 So also Christ glorified not himself to be made an high priest (as was Aaron); but he that said unto him, Thou art my Son, to day have I begotten thee.

Heb 2:17 Wherefore it behoved Him in all things to be made like unto His brethren, that He might become a merciful and faithful high priest before God, that He might be a propitiation for the sins of the people.

The prophecies of the Messiah say that he would be a priest:

Zec 6:13 Even he shall build the temple of the LORD; and he shall bear the glory, and shall sit and rule upon his throne; and he shall be a priest upon his throne