In Midian - This was a new revelation, and appears to have taken place after Moses returned to his father-in-law previous to his departure for Egypt.

And the Lord said unto Moses in Midian,.... After he had obtained leave of his father-in-law to quit Midian, but before he left it:

go, return into Egypt: that is, directly, immediately; before he had only given him a commission at large to go thither, but had not fixed the time when he should go; but now he orders him to set forward at once:

for all the men are dead which sought thy life; to take it away, the king of Egypt, and his ministers, and the friends of the Egyptian Moses had slain; and this is said to encourage him to go; and though Moses had never expressed his fear on this account, or made it an objection, yet it might lie secretly in his heart, and be one reason of his backwardness to go into Egypt, and which was now removed.

Return of Moses to Egypt. - Exodus 4:19-23. On leaving Midian, Moses received another communication from God with reference to his mission to Pharaoh. The word of Jehovah, in Exodus 4:19, is not to be regarded as a summary of the previous revelation, in which case ויּאמר would be a pluperfect, nor as the account of another writer, who placed the summons to return to Egypt not in Sinai but in Midian. It is not a fact that the departure of Moses is given in Exodus 4:18; all that is stated there is, that Jethro consented to Moses' decision to return to Egypt. It was not till after this consent that Moses was able to prepare for the journey. During these preparations God appeared to him in Midian, and encouraged him to return, by informing him that all the men who had sought his life, i.e., Pharaoh and the relatives of the Egyptian whom he had slain, were now dead.

And the LORD said unto Moses in Midian, Go, return into Egypt: for all the men are dead which sought thy life.

4:19 The Lord said unto Moses - This seems to have been a second vision, whereby God calls him to the present execution of the command given before.

19. all the men are dead which sought thy life-The death of the Egyptian monarch took place in the four hundred and twenty-ninth year of the Hebrew sojourn in that land, and that event, according to the law of Egypt, took off his proscription of Moses, if it had been publicly issued.

4:18-23 After God had appeared in the bush, he often spake to Moses. Pharaoh had hardened his own heart against the groans and cries of the oppressed Israelites; and now God, in the way of righteous judgment, hardens his heart against the teaching of the miracles, and the terror of the plagues. But whether Pharaoh will hear, or whether he will forbear, Moses must tell him, Thus saith the Lord. He must demand a discharge for Israel, Let my son go; not only my servant, whom thou hast no right to detain, but my son. It is my son that serves me, and therefore must be spared, must be pleaded for. In case of refusal I will slay thy son, even thy first-born. As men deal with God's people, let them expect so to be dealt with.