Genesis 36:33
And Bela died, and Jobab the son of Zerah of Bozrah reigned in his stead.
And Bela died,.... How long he reigned is not known with any certainty, nor whether he left any sons behind him; if he did, they did not succeed him in the throne; for
Jobab the son of Zerah of Bozrah reigned in his stead: this king some have thought to be the same with Job, and from whom one of the books of Scripture has its name; but neither their names, nor age, nor country agree: who this Jobab and his father Zerah were cannot be said: they seem to be of the same country in which Jobab reigned, since he is said to be of Bozrah, a famous city of Idumea, after spoken of in the prophets Isaiah and Jeremiah and others, Isaiah 34:6; Jarchi takes it to be a city of Moab, and indeed it is sometimes placed in Moab, and sometimes in Edom, it being on the borders of both, and sometimes belonged to the one and sometimes to the other. According to Mr. Bedford {k}, this king began his reign, A. M. 2135, so that the former king must have reigned about forty two years; which is a space of time he allows to each successor, taking them one with another, the particular and exact time of each reign he not being able to fix.
{k} Scripture Chronology, p. 327.