Exodus 4:20
19 The Lord said to Moses in Midian, “Go back to Egypt, because all the men who were seeking your life are dead.” 20 Then Moses took his wife and sons and put them on a donkey and headed back to the land of Egypt, and Moses took the staff of God in his hand. 21 The Lord said to Moses, “When you go back to Egypt, see that you do before Pharaoh all the wonders I have put under your control. But I will harden his heart and he will not let the people go.
LXX Exodus 4:20
19 And the Lord said to Moses in Madiam, Go, depart into Egypt, for all that sought thy life are dead. 20 And Moses took his wife and his children, and mounted them on the beasts, and returned to Egypt; and Moses took the rod which he had from God in his hand. 21 And the Lord said to Moses, When thou goest and returnest to Egypt, see—all the miracles I have charged thee with, thou shalt work before Pharao: and I will harden his heart, and he shall certainly not send away the people.
Notes and References
"... The Greek translation, the Septuagint, changes 'ass' to 'beasts of burden.' Commentators suggest the honor of Moses' wife as the reason for the emendation, for it would be improper for a woman of Moses' wife's stature to ride on a lowly ass. However, our targumist does not deviate from the literal translation of the biblical word hachamor. He translates it exactly as chamara, which may mean an ass, or the ass. Rashi, relying on a Midrash, states that the definite article, 'the,' implies the special ass. This is the ass upon which Abraham rode on his way to Mount Moriah to offer Isaac as a sacrifice, and that will, ultimately, be mounted by the King Messiah ..."
Drazin, Israel, and Stanley M. Wagner Onkelos on the Torah, Exodus: Understanding the Bible Text (pp. 21-22) Gefen, 2006