Meekness

But the man Moses was very meek, above all men that were upon the face of the earth. - Num 12:3

From this chapter alone we can learn from the three things Moses did as proof of his meekness:
1) In his writing, he does not hide but admits his mistake and weakness in taking a Cushite/Ethiopian woman as his second wife (vs 1-2).
2) He did not try to vindicate himself when questioned by his siblings but instead left it to God. God honoured that (vs 7-10).
3) He still prayed for his accusers (vs 13).