John Calvin Commentary Numbers 12:3

"Now the man Moses was very meek, above all the men that were upon the face of the earth." — Numbers 12:3 (ASV)

Now the man Moses was very meek. This parenthesis is inserted so that we might perceive that God was not moved by any complaint of Moses to be so greatly angry with Aaron and Miriam. It is said that “the Lord heard”—that is, to undertake the cause in His role as Judge. It is now added that He spontaneously summoned the criminals to His tribunal, even though no accuser requested that justice be done for him.

For this is the significance of the praise of his meekness, as if Moses had said that he submitted in silence to the wrong because, in his meekness, he imposed patience on himself. Moreover, he does not praise his own virtue for the sake of boasting, but to exhort us by his example, and, if we happen to be treated with indignity, to wait quietly and calmly for the judgment of God.

For from where does it come that, when anyone has injured us, our indignation overwhelms our feelings, and our pain boils up without limit, except because we do not believe that our troubles are noticed by God until we have made loud and noisy complaints? This passage, then, teaches us that although the good and gentle refrain from reproaches and accusations, God nevertheless keeps watch for them. While they are silent, the wickedness of the ungodly cries out to God and is heard by God.

Again, the silence of long-suffering itself is more effective before God than any cries, however loud. But if God does not immediately proceed to execute vengeance, we must bear in mind what is written elsewhere: that the blood of Abel cried out after his death, so that the murder Cain had committed would not go unpunished (Genesis 4:10).