Bible Notes Online - Numbers 12 - ESV
Commentary

v1-2: Miriam and Aaron began to speak against Moses. This was a difficult time for him, as even those closest to him attacked him.

v3: The meek and humble man does not defend himself; he looks to the Lord to vindicate him. Yet this was not inconsistent with his clear leadership qualities.

v6-8: The Lord had chosen Moses, "my servant". We are not to speak against God's anointed (see 1 Sam 24.6). The root of the attack seems to have been jealousy, since Moses enjoyed a greater intimacy with God that his older brother and sister.

The words from v7, "he is faithful in all my house," are quoted in Heb 3.2-6, where the writer teaches Christ's supremacy over Moses.

v10: The punishment for Miriam was to bear leprosy for a time. She had to remain outside the camp for 7 days (v14-15). The punishment was doubtless a warning to others also, as the whole nation did not move on until she was brought back.