While they were at Hazeroth, Miriam and Aaron spoke against Moses because of the Cushite woman whom he had married (for he had indeed married a Cushite woman);
and they said, "Has the Lord spoken only through Moses? Has he not spoken through us also?" And the Lord heard it.
Now the man Moses was very humble, more so than anyone else on the face of the earth.
References for Numbers 12:3
Suddenly the Lord said to Moses, Aaron, and Miriam, "Come out, you three, to the tent of meeting." So the three of them came out.
Then the Lord came down in a pillar of cloud, and stood at the entrance of the tent, and called Aaron and Miriam; and they both came forward.
And he said, "Hear my words: When there are prophets among you, I the Lord make myself known to them in visions; I speak to them in dreams.
Not so with my servant Moses; he is entrusted with all my house.
With him I speak face to face—clearly, not in riddles; and he beholds the form of the Lord. Why then were you not afraid to speak against my servant Moses?"
And the anger of the Lord was kindled against them, and he departed.