And he said unto Moses
By a messenger, as Jarchi: or by a written letter, as Aben Ezra: or, as the Septuagint version, "it was told to Moses, thy father" for as yet he was not come to him, as appears by Moses going forth to meet him:
I thy father in law Jethro am come to thee:
or, "am coming" F13; for, as yet, he was not in his presence, and they were not personally present face to face: the Targum of Jonathan adds, "to become a proselyte"; but it seems that before, as well as now, he had been a worshipper of the true God, and always speaks like one that had had the fear of God before him continually:
and thy wife, and her sons with her;
this he thought fit to acquaint him of by messenger or letter, that he might be in expectation of them, and not be surprised at once with their appearance: besides, as some observe, and not amiss, after the late attack of the Amalekites upon their rear, guards or sentinels might be placed in the outer parts of the camp for its safety, and who would not easily, without order, let strangers pass into it, and therefore previous notice was necessary to get admission.
The Brenton translation of the Septuagint is in the public domain.