Now the priest of Midian had seven daughters
Who being a descendant of Abraham might have retained the knowledge of the true God, and might be a priest of his, as Melchizedek was, or otherwise it may be thought improbable that Moses would have married his daughter, as he afterwards did; and so Aben Ezra says, he was a priest of God; though the word is sometimes used of a prince, ruler, and governor; and is so rendered here by the Targums of Onkelos and Jonathan; and Artapanus F18, an Heathen writer, expressly calls him (arcwn) , a "prince" of those places, that is, of Arabia; he might be both prince and priest, as Melchizedek before mentioned was, and as has been the usage of many countries:
and they came and drew water, and filled the troughs to water their
which is no contradiction to their being daughters either of a priest or a prince, which were both high titles and characters; since it was usual in those early times, and in those countries, for the sons and daughters of considerable persons to be employed in such services; (See Gill on Genesis 29:9).
F18 Ut supra, (Apud Euseb. Praepar. Evangel. l. 9. c. 27.) p. 434.