Scripture strongly emphasises that Jesus is of the house of David. So he is of royal descent. But from whom is he descended? According to the gospels, it is Joseph who gives his adoptive son his royal line from David. This is of great importance because the Messiah must be ‘the son of David’.
But from whom is Jesus’ mother descended?
An initial hypothesis, the simplest one, suggests that Mary, wife of Joseph, was also of David’s line. In this case, Jesus would unquestionably be “made of the seed of David according to the flesh” (Rom. 1: 4). Isn’t it fairly probable, in a civilisation where people from the same tribe, or indeed from the same clan, readily married each other, that Joseph would choose as his wife a young lady from the same line of David as himself?
“Take a wife of the seed of thy fathers, and take not a strange woman to wife, which is not of thy father's tribe” (Tob. 4: 12).
The apocryphal gospels, especially the much-revered Proto-Gospel of James, unequivocally affirm that Mary is of the house of David. The Venerable Bede (735 AD) thinks the same and teaches that Mary was of the house of David, just as Joseph was “because under the Law every man was to choose his wife from within his tribe or family”.
But this hypothesis runs into a difficulty: if Mary is a daughter of David, why is it that the canonical gospels do not clearly refer to this? Why do they forego a point that would fully support their message? Their concern to underline the Messianic nature of Jesus and the conception of the virgin would have quite naturally led them to highlight the Virgin’s lineage from David.
This being the case, how are we to understand the gospels’ silence on this subject? Was the law on marrying within the tribe obvious enough for there to be no need to refer to the wife’s tribe once that of her husband had been mentioned? This is not certain. Moreover, we read in the book of Exodus that Aaron had himself taken a wife from the tribe of Judah whose first name was indeed Elizabeth! (Ex. 6:3). This proves that marriages outside the tribe were also possible.
The silence of the gospel writers casts a doubt on our first hypothesis. It is thus appropriate to examine the second. That the Virgin is not of the royal house of David (and therefore of the tribe of Judah), but rather of the priestly tribe of Levi. Indeed, Mary is Elizabeth’s kinswoman (Luke 1:36) who is of the daughters of Aaron (Luke 1: . Shouldn’t we therefore consider the possibility that Mary is also of the tribe of Levi, or indeed a daughter of Aaron herself? Saint Ephraim (373 AD) did not hesitate to maintain that “The words of the angel to Mary: ‘Elizabeth, your kinswoman’ portrays Mary as being of the house of Levi .
Does Jesus have priestly ancestors through his Mother’s lineage?
In this case, Jesus himself would have priestly ancestors through his mother. Through him the two lines of Messianic expectation would be brought together: the priestly and the royal. Through Joseph he would be a son of David, and through Mary a son of Aaron. He would be at once both King and Priest.
Now in past times the Jewish tradition, represented especially by the Essenians, expected not one but even two Messiahs. The royal Messiah was to come first as the descendant of David and as an eschatological war leader who would ensure peace for Israel by bringing down the enemies of the Lord. Then this Royal Messiah would move aside once his mission of quelling God’s enemies had been accomplished, making way for the priestly Messiah, the son of Aaron arrayed at last as the Great High Priest. Traces of this Messianic dualism may be found in several Biblical texts .
In order to merge together these two Messianic lines, certain Jewish writings maintain that a single Messiah shall be both King and Priest, from both the tribe of Judah and that of Levi .
This would be Jesus’ position if the hypothesis that Mary is descended from Levi were accepted. Jesus has no need of this for him to be the Great King and High Priest that our faith confesses ( cf. Heb. 3: 1) but this would fit with his Messianic nature.
It remains impossible to resolve the question of whether the Virgin is descended from one tribe or another. Even Luke, who even takes pleasure in emphasising the solid Judaic roots of his biblical figures (Elizabeth, daughter of Aaron, Joseph, son of David, Anna, daughter of Phanuel of the tribe of Asher....), has nothing to say on this subject.
Perhaps this silence has some spiritual significance?
Mary is not from any tribe in particular because she is the Mother of all living people; she is neither from the house of David nor from the house of Levi because she is quite simply from the house of God .
Thus she receives no special blessing as each of the12 twelve tribes do (cf. Genesis 49). She is simply “blessed among all women”.
 Saint Ephraim, Commentary on the Diatessaron no. 25 See St. Gregory of Nazianzus: “You are perhaps wondering how Christ is descended from David? Mary is obviously of Aaron’s family since in the words of the angel she is the cousin of Elizabeth. Here can be seen the effect of God’s providential plan, who wished to join royal blood to the race of priests so that Jesus, who is both priest and king, also had his earthly ancestry kings and priests (quoted in Catena Aurea p.40). Conversely, St. Augustine says: “ Since the same gospel writer tells us that the husband of Mary was Joseph, and that the mother of Christ was a virgin, and that Christ is of the line of David, what can we believe, other than that Mary was not outside David’s lineage.”
 “These are the two anointed ones, who stand before the Lord of the whole world.” (Zechariah 4: 14 JB)
 See the Testament of the Twelve patriarchs (Sim. 7: 2)
 cf. Ephesians 2: 19: “Now therefore ye are no more strangers and foreigners, but fellowcitizens with the saints, and of the household of God”.
1. Translations of quotations are taken directly from the King James’ Version of the Bible.