Moses was not simply kvetching, but expressing legitimate despair. God heard his cry.
In response, He put the spirit of Moses on 70 elders to ease the burden of leadership.
An Ethiopian Israeli woman plays a djembe, a goblet-shaped drum
originally from West Africa.
As if the sin of thousands of Israelites complaining were not enough to bear, his brother and sister, Aaron and Miriam, publicly criticized Moses for marrying a Cushite, (Ethiopian), woman. They became envious of his status with God as a prophet and leader.
After all, God gave Miriam and Aaron His Spirit to prophecy as well—but not as much or in the same way as He gave to Moses.
A prophet should know better than to envy another prophet.
God asked Miriam and Aaron, “Were you not afraid to speak against My servant, Moses?” (Numbers 12:8)
After seeing thousands of Israelite's struck dead from their complaining, they should have been very afraid, but they weren’t.
As a consequence of their verbal attack against Moses, Miriam was struck with leprosy. (Numbers 12:10)
Leprosy is a punishment for the sin of Lashon Hara, literally, evil tongue. It is the use of truth, for a wrongful purpose; i.e., to lower another persons status in the eyes of God and people while seemingly elevating our own in the eyes of people.
The truth is never to be used as a weapon of hate or envy. While we are to be speakers of the truth, we are to do so with love.
"Speaking the truth in love, we will grow to become, in every respect, the mature body of Him who is the head, that is, Messiah." (Ephesians 4:15)