"And Dhu al-Nun" means: Yunus (Jonah). Qatadah and others said: Al-Nun is the whale.
Muhammad said: His statement "And Isma'il (Ishmael), and Idris (Enoch), and Dhu al-Kifl" is in the accusative case (mansub) based on the implicit meaning: "And mention." The same applies to his statement: "And Dhu al-Nun." "When he went off in anger" [at his people]: "and he thought that We would not restrict him." Qatadah said: It means that We would not punish him for what he did.
Muhammad said: The root of the word implies constriction, like His statement: "But when he restricts his provision for him," meaning: narrows it. From this is their saying: "So-and-so is muqaddar 'alayhi (one whose provision is restricted) and muqattar (tightened)."
﴿وَذَا النُّون﴾ يَعْنِي: يُونُسَ، قَالَ قَتَادَةُ وَغَيْرُهُ: النُّونُ: الْحُوتُ.
قَالَ مُحَمَّدٌ: قَوْلُهُ: ﴿وَإِسْمَاعِيل وَإِدْرِيس وَذَا الكفل﴾ مَنْصُوبٌ عَلَى مَعْنَى: وَاذْكُرْ، وَكَذَلِكَ قَوْله: ﴿وَذَا النُّونِ﴾. ﴿إِذْ ذَهَبَ مُغَاضِبًا﴾ [لِقَوْمِهِ]: ﴿فَظَنَّ أَنْ لَنْ نَقْدِرَ عَلَيْهِ﴾ قَالَ قَتَادَةُ: يَعْنِي: أَنْ لَنْ نُعَاقِبَهُ بِمَا صَنَعَ.
قَالَ مُحَمَّدٌ: أَصْلُ الْكَلِمَةِ: الضِّيقُ؛ كَقَوْلِهِ: ﴿فَقَدَرَ عَلَيْهِ رزقه﴾ أَيْ: ضَيَّقَ، وَمِنْ هَذَا قَوْلِهِمْ: فُلَانٌ مُقَدَّرٌ عَلَيْهِ وَمُقَتَّرٌ.
