job 29:18 Then I said, I shall die in my nest, and I shall multiply my days as the sand. - Free Bible Online

      18. I said--in my heart (Ps 30:6).
      in--rather, "with my nest"; as the second clause refers to long life. Instead of my family dying before me, as now, I shall live so long as to die with them: proverbial for long life. Job did realize his hope (Job 42:16). However, in the bosom of my family, gives a good sense (Nu 24:21; Ob 4). Use "nest" for a secure dwelling.
      sand-- (Ge 22:17; Hab 1:9). But the Septuagint and Vulgate, and Jewish interpreters, favor the translation, "the phœnix bird." "Nest" in the parallel clause supports the reference to a bird. "Sand" for multitude, applies to men, rather than to years. The myth was, that the phœnix sprang from a nest of myrrh, made by his father before death, and that he then came from Arabia (Job's country) to Heliopolis (the city of the Sun) in Egypt, once in every five hundred years, and there burnt his father [HERODOTUS, 2:73]. Modern research has shown that this was the Egyptian mode of representing hieroglyphically a particular chronological era or cycle. The death and revival every five hundred years, and the reference to the sun, implies such a grand cycle commencing afresh from the same point in relation to the sun from which the previous one started. Job probably refers to this.

JFB.