See, the days are coming, says the Lord, when I will give to David a true Branch, and he will be ruling as king, acting wisely, doing what is right, and judging uprightly in the land.

And you, Beth-lehem Ephrathah, the least among the families of Judah, out of you one will come to me who is to be ruler in Israel; whose going out has been purposed from time past, from the eternal days.

You Beth-lehem, in the land of Judah, are not the least among the chiefs of Judah: out of you will come a ruler, who will be the keeper of my people Israel.

Because it is clear that our Lord comes out of Judah, and Moses said nothing about priests from that tribe.

Birthright was

Blessings of sons, old and young, to the father: blessings of the oldest mountains and the fruit of the eternal hills: let them come on the head of Joseph, on the crown of him who was separate from his brothers.

Because those of whom he had knowledge before they came into existence, were marked out by him to be made like his Son, so that he might be the first among a band of brothers:

General references

The generations of the sons of Judah were numbered by their families and their fathers' houses, every male of twenty years old and over who was able to go to war;

These are the families of Judah as they were numbered, seventy-six thousand, five hundred.

Then when he gives his property to his sons for their heritage, he is not to put the son of his loved one in the place of the first son, the son of the hated wife: