"To lead in melodies. It is known in Judah, God is in Israel. This is what the verse says (Hosea 5:9): 'Ephraim shall become a desolation in the day of rebuke; among the tribes of Israel I make known what is sure.' When the ten tribes were exiled and only the tribes of Judah and Benjamin remained, the nations of the world began to say that they are no different than other nations, as they are the guests of God.
Therefore, they were not exiled. As it says: 'Among the tribes of Israel I make known what is sure.' At that same moment, God became known in Judah, and His name was great in Israel. Rabbi Yehuda bar Elai said: 'When the Israelites stood at the sea, they argued with one another, one saying, "I will go down first," and the other saying, "I will go down first."
From this, Nachshon ben Aminadav jumped into the sea, and regarding him, it is written (Psalms 69:2): "Save me, O God, for the waters have come up to my neck." Moses stood in prayer, and the Holy One, blessed be He, said to him: "The Israelites are in distress, and you prolong your prayer? Speak to the children of Israel and let them go forward." You, therefore, lift up your rod.
Therefore, Judah merited to have sovereignty in Israel, as it says (Psalms 114:2-3): "Judah became God's sanctuary, Israel His dominion. The sea saw and fled." It is known in Judah, God is great in Israel, for He is great among Israel. It was said to him: "When you perform a kindness for Judah, it is as if you are performing a kindness for all of Israel, as all of Israel is called by the name of Judah."
Another explanation for why Judah merited sovereignty is that his disciples asked Rabbi Tarfon in the shade of the Shukei Binyamin (an area in Jerusalem) why Judah merited sovereignty. He answered them, "Because he confessed regarding the incident with Tamar." They told him that Dia should atone for her immorality. He asked why, and they replied that it was because he had said, "What profit is there if we kill him?" (Genesis 37:26).
They also told him that Dia should atone for his sale of Joseph, and he responded that it was because he had said, "Please let your servant stay as a slave to my lord instead of the boy" (Genesis 44:33). They then asked him about the evening pledge that he had fulfilled, and he replied, "By what merit did I do it? Only because I leaped into the waves of the sea." For when all the tribes were standing and none of them would descend into the sea, one tribe would say, "I will go down first," and another would say, "No, I will go down first."
Benjamin, however, wanted his tribe to be the first to go down. So Nachshon ben Aminadav jumped into the waves with his tribe, even though they tried to stone him, and he was saved. The verse in Psalms (68:28) states, "Benjamin, the youngest, is their ruler. The leaders of Judah come with their throngs."
This refers to the fact that the people of Judah wanted to stone him and were delayed, while Benjamin went ahead and was the first to descend. In this way, Nachshon merited to become a king, as it is written (Psalms 114:2), "Judah became God's sanctuary, Israel His dominion." Therefore, the kingship of Israel belonged to the tribe of Judah. "God is known in Judah."