Numbers 12:11

“And Aaron said unto Moses, alas, my lord! etc.] The word for “alas” is generally interpreted by the Jewish writers as a note of beseeching and entreating, as it is here by the Targums of Onkelos and Jonathan, “I beseech thee, my lord,” or “upon me, my lord” f149, be all the blame; such was his tenderness to his sister, and the compassion he had on her; and such reverence and respect did he show to Moses his brother, though younger than he, because of his superior dignity as a prophet, and chief magistrate, and prime minister, and servant of the Lord, calling him “my lord”: I beseech thee, lay not the sin upon us; the punishment of it, bear not hard upon us, or suffer us to be punished in a…”

“On the humble and penitential submission of Aaron, Moses interceded for both the offenders, especially for Miriam, who was restored; not, however, till she had been made, by her exclusion, a public example [Num 12:14-15].”

“Miriam, as a prophetess (compare Exodus 15:20-21) no less than as the sister of Moses and Aaron, took the first rank among the women of Israel; and Aaron may be regarded as the ecclesiastical head of the whole nation. But instead of being grateful for these high dignities they challenged the special vocation of Moses and the exclusive authority which God had assigned to him. Miriam was the instigator, from the fact that her name stands conspicuously first Numbers 12:1, and that the punishment Numbers 12:10 fell on her alone. She probably considered herself as supplanted, and that too by a foreigner. Aaron was misled this time by the urgency of his sister, as once before Exodus 32:0 by that…”

“Lay not the sin - Let not the guilt and punishment of this sin rest upon us, upon her in this kind, upon me in any other kind, but pray to God for the pardon and removal of it. Numbers 12:12”

“I beseech thee: Exo 12:32; Sa1 2:30, Sa1 12:19, Sa1 15:24, Sa1 15:25; Kg1 13:6; Jer 42:2; Act 8:24; Rev 3:9 lay not: Sa2 19:19, Sa2 24:10; Ch2 16:9; Psa 38:1-5; Pro 30:32 Numbers 12:12”

“When Aaron saw his sister smitten in this way, he said to Moses, "Alas! my lord, I beseech thee, lay not this sin upon us, for we have done foolishly;" i.e., let us not bear its punishment. "Let her (Miriam) not be as the dead thing, on whose coming out of its mother's womb half its flesh is consumed;" i.e., like a still-born child, which comes into the world half decomposed. His reason for making this comparison was, that leprosy produces decomposition in the living body. Numbers 12:13”