Allah Almighty says: (Then the whale swallowed him up while he was blameworthy.)
Yunus (Jonah) pbuh was a messenger sent by Allah Almighty to the people of Nineveh.
He was blameworthy because he had admonished his people and warned them of Allah’s Wrath but when the punishment did not fall on them and still, they didn’t believe, he left them angry at them, and they were angry with him. He left them without permission from his Lord and abandoned his call to Allah.
The call to people requires patience, and Yunus did not have that patience.
(Then the whale swallowed him up while he was blameworthy.) Al-Saffat 37:142
يونس عليه السلام بعثه الله إلى قومه في أرض نينوى.
وسبب لومه أنه كان قد أنذر قومه بحلول عقاب الله عليهم فلما لم يقع العقاب ولم يؤمن القوم خرج وقد غضب عليهم و غضبوا عليه. وَهُوَ مُسْتَحِقٌّ لِلْمَلاَمَةِ عَلَى مَا فَعَلَ مِنْ خُرُوجِهِ مِنْ بَيْنِ أَظْهُرِ قَوْمِهِ بِغَيْرِ إِذْنِ رَبِّهِ، وَتَخَلِّيهِ عَنْ دَعْوَتِهِمْ إِلَى اللهِ،
والدَّعْوَةُ تَسْتَدْعِي الصَّبْرَ والثَّبَاتَ وهو لم يصبر على قومه.
(فَالْتَقَمَهُ الْحُوتُ وَهُوَ مُلِيمٌ )
الصافات 37: 142