His father-in-law is called here [in
Exo 3:1] Jethro, and seemingly this presents a difficulty, for earlier the
Bible refers to him as Reuel. The difficulty is not to be explained by the
usual premise that the redactor excerpted mechanically texts from different
sources, for it is inconceivable that the editor should not have noticed the
discrepancy between the sources, and should unwittingly have put the two conflicting
names within a few lines of each other. It seems more probable to suppose that
there existed among the Israelites variant traditions concerning the man’s
name, which were well known to the people, and that the Torah deliberately
chose the name Reuel when alluding to him only as the priest of Midian, but
preferred to use here, when speaking of him as Moses’ faither-in-law, the name
Jethro [יִתְר֥וֹ Yithrō, from a stem meaning ‘abundance’, ‘superiority’],
the more honoured designation, which points to his pre-eminent status. His
importance rose in our estimation when he became Moses’ father-in-law. (Umberto
Moshe David Cassuto, A Commentary on the Book of Exodus [trans. Israel
Abrahams; Varda Books, 2005], 30, comment in square brackets added for
clarification)