His sons, Gershom, Exodus 2:22, and Eliezer, Exodus 18:4, whom he intended to carry with him; but afterwards observing that they were like to be impediments to him in his great business, and being well assured that it would not be long ere he returned to them, he sent them back to Jethro, as may seem from Exodus 18:5. Upon an ass: one ass might be sufficient for her and her two children, because one of them was but little, Exodus 4:25. Or ass may be put for asses, which changes of the numbers is very frequent in Scripture. The rod of God; his shepherd's rod so called, partly because it was appropriated to God's special service, to be the instrument in all his glorious works; and partly to show that whatsoever was done by that rod, was not done by any virtue in the rod, or in Moses's hand, but merely by the power of God, who was pleased for the greater confusion of his enemies to use so mean an instrument.
Related Commentaries of Exodus 4:20
Exodus 4:20
20 And Moses took his wife and his sons, and set them upon an ass, and he returned to the land of Egypt: and Moses took the rod of God in his hand.