Then Jethro, Moses' father in law, took Zipporah, Moses' wife, after he had sent her back,

He took Sephora the wife of Moses whom he had sent back:

Then Jethro, Moses's father-in-law, took Zipporah Moses's wife, after he had sent her back,

and Jethro, father-in-law of Moses, taketh Zipporah, wife of Moses, besides her parents,

he brought Zipporah, the wife of Moses, whom he was to return to him,

Tulit ergo Jethro socer Mosis uxorem Mosis, postquam miserat eam,

After he had sent her back - Why Zipporah and her two sons returned to Midian, is not certainly known. From the transaction recorded Exodus 4:20, Exodus 4:24, it seems as if she had been alarmed at the danger to which the life of one of her sons had been exposed, and fearing worse evils, left her husband and returned to her father. It is however possible that Moses, foreseeing the troubles to which his wife and children were likely to be exposed had he taken them down to Egypt, sent them back to his father-in-law till it should please God to deliver his people.
Jethro, now finding that God had delivered them, and totally discomfited the Egyptians, their enemies, thought it proper to bring Zipporah and her sons to Moses, while he was in the vicinity of Horeb.

Then Jethro, Moses' father in law, took Zipporah, Moses' wife, after he had (a) sent her back,
(a) It may seem that he sent her back for a time to her father for her impatience, lest she should be a hinderance to his calling, which was so dangerous, (Exodus 4:25).

Then Jethro, Moses's father-in-law, took Zipporah, Moses's wife,.... When he had heard of the above things, he determined to pay Moses a visit, and congratulate him on that account; and he took his daughter, the wife of Moses, along with him, to deliver her to her husband, to share with him in his cares and troubles; as to partake with him of his honours and dignity, so to bear part with him in his burdens, so far as she was capable of:
after he had sent her back: upon his call and mission to Egypt, he took his wife and children with him; but upon an affair which occurred in the inn by the way, he sent them back again to his father-in-law, where they had remained ever since, see Exodus 4:24. Jarchi says this was done at meeting with Aaron his brother, Exodus 4:27, and relates a conversation between them upon it. As that Aaron should say to him, who are these? to which he replied, this is my wife, I married her in Midian, and these are my sons: he further said to him, and where art thou carrying them? he replied, to Egypt; says he, by reason of those who are before there, we are in straits, and thou wilt add unto them; upon which he said to his wife, go back to thy father's house, and she took her sons and went thither. Kimchi (f) observes, that some render the words "after her gifts"; whose sense, according to Aben Ezra, is, after she had sent gifts to her husband; but others more probably interpret it of gifts sent by him to her to engage his father-in-law to let her come to him, as well as to prevail upon her to come; perhaps it may be better rendered, "after her messenger"; that is, either after the messenger sent to her by Moses, to acquaint her and her father of what had been done for him, or after the messenger she sent to him, to let him know that she intended shortly to be with him; though perhaps, after all, nearer to our version and others, it may be rendered, "after her dismissions" (g); the dismission or sending away of her and her sons, as before related; for this is by no means to be interpreted of a divorce of her; after which she was brought again to her husband; for there is no reason to believe that ever anything of that kind had passed, as some have thought (h): the plain case seems to be this, that Moses finding his family would be exposed to danger, or would be too great an incumbrance upon him in the discharge of his great work he had to do in Egypt, sent them back to his father-in-law until a fit opportunity should offer of their coming to him, as now did.
(f) Sepher Shorash. rad. "post dona vel donationes ejus"; so some in Vatablus and Drusius. (g) "post dimissiones ejus", Pagninus, Montanus, Drusius. (h) Vid. Selden. Uxor. Hebr. p. 629.