Thank you for putting forward an example of non-eternal `olam. But surely the point here was that Jonah thought that this was indeed forever, i.e. that he was dead, that he was in Sheol itself (v.2), the eschatological pit (shaxat, v.6, mistranslated "corruption" in KJV) - until his miraculous deliverance.
...
"I went down to the bottoms of the mountains; the earth with her bars was about me for ever [l'olam]: yet hast thou brought up my life from corruption, O LORD my God." -- Jonah 2:6 KJV
In this occurrence, "forever" lasted for only three days.
Archive powered by MHonArc 2.6.24.