Musar for Bava Batra 30:9
א"ר יוחנן דורו של איוב שטוף בזמה היה שנאמר הן אתם כולכם חזיתם ולמה זה הבל תהבלו וכתיב (שיר השירים ז, א) שובי שובי השולמית שובי שובי ונחזה בך אימא בנבואה דכתיב (ישעיהו א, א) חזון ישעיהו בן אמוץ א"כ למה זה הבל תהבלו למה לי
All these Tannaim agree that Job was from Israel, except those who say [that he lived in the days of Jacob]. [This must be so,] for if you suppose that [they regarded him as] a heathen, [the question would arise,] after the death of Moses how could the Divine Presence rest upon a heathen,<span class="x" onmousemove="('comment',' And all agree that Job was a prophet. ');"><sup>16</sup></span> seeing that a Master has said, Moses prayed that the Divine Presence should not rest on heathens, and God granted his request as it says, That we be separated, I and thy people, from all the people that are upon the face of the earth.<span class="x" onmousemove="('comment',' Ex. XXXIII, 16. This difficulty, however, would not arise if we suppose Job to have been in the days of Jacob. ');"><sup>17</sup></span>