I beleive the verses you are looking for are Numbers 12:1-10
"And Miriam and Aaron spake against Moses because of the Ethiopian woman whom he had married: for he had married an Ethiopian woman. And they said, "Hath the LORD indeed spoken only by Moses? hath he not spoken also by us?" And the LORD heard it.
Now the man Moses was very meek, above all the men which were upon the surface of the earth. And the LORD spake suddenly unto Moses, and unto Aaron, and unto Miriam, Come out ye three unto the tabernacle of the congregation. And they three came out.
And the Lord came down in the pillar of the cloud, and stood in the door of the tabernacle, and called Aaron and Miriam: and they both came forth. And he said, Hear now my words: If there be a prophet among you, I the LORD will make myself known unto him in a vision, and will speak unto him in a dream. My servant Moses is not so, who is faithful in all my house.WIth him will I speak mouth to mouth, even apparently, and not in dark speeches, and the similitude of the LORD shall he behold: wherefore then were ye not afraid to speak against my servant Moses?
And the anger of the LORD was kindled against them, and he departed. And the cloud departed from off the tabernacle, and behold, Miriam became leprous, white as snow, and Aaron looked upon Miriam, and behold, she was leprous."