(NLT translation, which is my favourite at the moment)
1 While they were at Hazeroth, Miriam and Aaron criticized Moses because he had married a Cushite woman.
2 They said, “Has the Lord spoken only through Moses? Hasn’t he spoken through us, too?” But the Lord heard them.
3 (Now Moses was very humble — more humble than any other person on earth.)
4 So immediately the Lord called to Moses, Aaron, and Miriam and said, “Go out to the Tabernacle, all three of you!” So the three of them went to the Tabernacle.
5 Then the Lord descended in the pillar of cloud and stood at the entrance of the Tabernacle. “Aaron and Miriam!” he called, and they stepped forward.
6 And the Lord said to them, “Now listen to what I say:
“If there were prophets among you,
I, the Lord, would reveal myself in visions.
I would speak to them in dreams.
7 But not with my servant Moses.
Of all my house, he is the one I trust.
8 I speak to him face to face,
clearly, and not in riddles!
He sees the Lord as he is.
So why were you not afraid
to criticize my servant Moses?”
9 The Lord was very angry with them, and he departed.
10 As the cloud moved from above the Tabernacle, there stood Miriam, her skin as white as snow from leprosy. When Aaron saw what had happened to her,
11 he cried out to Moses, “Oh, my master! Please don’t punish us for this sin we have so foolishly committed.
12 Don’t let her be like a stillborn baby, already decayed at birth.”
13 So Moses cried out to the Lord, “O God, I beg you, please heal her!”
14 But the Lord said to Moses, “If her father had done nothing more than spit in her face, wouldn’t she be defiled for seven days? So keep her outside the camp for seven days, and after that she may be accepted back.”
15 So Miriam was kept outside the camp for seven days, and the people waited until she was brought back before they traveled again.
16 Then they left Hazeroth and camped in the wilderness of Paran.

Why is this a favourite passage?
There is much worth pondering in this passage. A few thoughts:
1) Like many in authority, Moses arouses resentment in those around him. It is as if Miriam and Aaron (brother and sister to Moses, remember) resent the admission into Moses’ inner circle of someone new. This is rivalrous desire.
2) Unlike most people, Moses does not play their game – he is genuinely humble – but the Lord then acts on his behalf. Moses does not assert himself – the Lord defends Moses from what his relatives are doing. Something of a theme with Moses (‘you have only to stand and watch…’)
3) Moses intercedes for his sister – there is no anger on display. Moses doesn’t try to stand in God’s place of judgement.
4) The people wait for Miriam.

I just find this a very human vignette, and a story which says a great deal about Moses’ character.