Exodus 4:19-20 a J. Moses is Recalled by Yahweh to Egypt. This piece probably originally followed Exodus 2:23 a, the narrative of the revelation at the bush having been antedated by the compiler, to dovetail in with E's story. The pl. sons is probably due to the editor, to fit Exodus 18:2-4: in J (Exodus 2:24 and Exodus 4:25) only one son is mentioned.
Exodus 4:20 b E continues Exodus 4:17.