Translation of the verse 144 from Surah As-saffat : Number of verses 182 - - page 451 - Part 23.
He would have indeed remained inside its belly (the fish) till the Day of Resurrection.
He would have remained inside its belly until the Day they are resurrected.
(37:144) he would certainly have remained in its belly till the Day of Resurrection. *81
*81) This does not mean that the fish would have lived till Resurrection and the Prophet Jonah would have remained alive in its belly till then, but that the fish's belly would have become his grave till Resurrection. The famous commentator Qatadah has given this same meaning of this verse. (Ibn Jarir).
Source : As-saffat Verse 144: He would have remained inside its belly until the Day they are resurrected.