Now, we want to turn our attentions just a moment to the attitude of Miriam and Aaron. They thought that Moses had done wrong. They wanted to correct him. God was speaking to them, truly, but He said, “If there be one among you who’s a prophet, I’ll visit him in miracles or visions, and appear to him in dreams, and so forth. But Moses, I have spoke mouth to mouth with him.” And Miriam was stricken with leprosy immediately, and Aaron run in, ’cause Miriam was Moses’ own sister. So it doesn’t pay to talk about God’s servant, does it? And so, God spoke to Aaron here, and told him, said, “Seeing that what he had done by Moses,” said, “didn’t you fear to say those things about him?” And so Aaron run to Moses and said his sister was stricken in there, white with leprosy, of course, and said, “Would you let her die.” And so Moses threw hisself before God and pleaded for her, and Miriam was stricken with leprosy though. She had to stay, and Israel halted their journey seven days according to the law till they could bring her out of the camp again.

Has the Lord Spoken Only to Moses?, 1953-11-30, West Palm Beach, FL, §2