John Calvin Commentary Numbers 12:2

"And they said, Hath Jehovah indeed spoken only with Moses? hath he not spoken also with us? And Jehovah heard it." — Numbers 12:2 (ASV)

And they said, Hath the Lord indeed spoken only by Moses? They pride themselves on their gift of prophecy, which should rather have taught them humility.

But such is the natural depravity of men, not only to abuse the gifts of God to the contempt of their brothers, but also to magnify them by their ungodly and sacrilegious boasting, so as to obscure the glory of their Author.

Miriam and Aaron had received the spirit of prophecy, so that the grace of God might shine forth in them; but from this they raise up clouds to throw darkness upon the light, which was far brighter in Moses.

They boast that they are prophets; why, then, do they not consider that there was no ground for glorying in this, since that which had been freely given to them by God was not their own? Again, why do they not correctly estimate their own insignificance in comparison with the excellence of Moses, and so, by willingly yielding to him, show that they set at its proper value what God had conferred on them respectively?

Therefore, lest the knowledge of those graces which God has entrusted to us should puff us up with pride and presumption, let us remember that the more each of us has received, the greater are our obligations to God and our brothers. Let us also reflect on how much is lacking in us, and how much God has also conferred on others, so that we prefer to ourselves those whom God has designed to honor.