Changing Judgement

Si praedixit Danihel sententiam Dei quae non potest immutari quomodo hortatur ad eleemosynas et misericordiam pauperum, ut Dei sententia commutetur? Facile solvitur Ezechiae regis exemplo, quem Esaias dixerat esse moriturum et Nenivitarum; adhuc tres dies et Nenive subvertetur; et tamen ad preces Ezechiae et Nenivitarum Dei sententia commutata est, non vanitate judicii, sed eroum conversione. Petrus Archidiaconus  Liber De Diversis Quaestiunculis, Questiones In Danielem  Source: Migne PL 96.1350b

If Daniel foretold the sentence of God, which cannot be changed, 1 how is it that the king is exhorted to be merciful and have pity on the poor, so that the sentence of God be changed? This is easily resolved by the example of King Hezekiah, whom Isaiah said was going to die, 2 and of the Ninevites, that in three days Nineveh would be overthrown, 3 for yet by the prayers of Hezekiah and the Ninevites the sentence of God was changed, and not because of a vain judgement but by their conversion. Peter of Pisa, The Book of Diverse Questions, Questions On Daniel 1 Dan 4.24-27 2 Isaiah 38.1 3 Jonah 3.4