Commentary for Numbers 12:13

אל נא רפא נא לה HEAL HER NOW, O GOD, I BESEECH THEE — Scripture intends to teach you by this form of prayer the correct altitude in social life — that if one is asking a favour of his fellow man he should first say two or three words of supplication and then solicit the favour (Sifrei Bamidbar 105).

א-ל נא רפא נא לה, he was pleading that Miriam should be healed forthwith so that she would not be subjected to the embarrassment of having to leave the camp.

ויצעק משה אל השם, Moses cried out to G'd, etc. The reason the Torah added the word לאמור, was to tell G'd that he had not felt offended at all and that such an assumption should not result in Miriam and Aaron assuming that he harboured some enmity against them although he wanted Miriam to be cured. It had been Aaron's words in verse 12 which had made Moses feel that he had to indicate that he never harboured any resentment against them.