Four refusals in, the Holy One's patience runs out. Targum Pseudo-Jonathan preserves the flash: the anger of the Lord was kindled against Mosheh. This is unusual. The Torah rarely describes God as angry with Moses, and the Targum does not soften the phrase.
And yet the anger is not punitive. It is generative. Out of divine frustration comes the appointment that will shape the entire priesthood: Is it not manifest before Me that Aharon thy brother speaking can speak?
The Brother Who Can Speak
The Targum plays on a Hebrew doubling — daber yedaber, literally speaking will speak — by rendering it as speaking can speak. Aaron is fluent in a way Moses is not. Where Moses stammers, Aaron flows.
And then the tender detail: behold, also, he cometh forth to meet thee, and will see thee and rejoice in his heart. The Targum emphasizes that Aaron is already en route. He is not waiting for Moses to arrive; he is walking toward him. And when he sees his younger brother, he will rejoice in his heart.
The sages of the Targumic tradition note that the older brother could have been jealous. Aaron had stayed in Egypt, endured the slavery, perhaps even served as a prophet himself (Shemot Rabbah 5:20). The younger brother — absent for forty years in Midian — returns with the commission. Aaron rejoices anyway.
The takeaway: God's anger, even at Moses, does not abandon him. It reroutes him. The stammerer is paired with the fluent. The reluctant prophet is given a brother who will speak for him — and who will, astonishingly, be happy about it.