Allah (Glorified and Exalted is He) says: "Now? And you had disobeyed before," because he believed at a time when Allah does not accept faith. The precedent of the ancients, among those who passed away before, has already been established that faith is not accepted when punishment descends.
يَقُول الله ﷿: ﴿آلآن وَقد عصيت﴾ لأَنَّهُ آمَنَ فِي حِينٍ لَا يَقْبَلُ اللَّهُ فِيهِ الإِيمَانَ؛ وَقَدْ مَضَتْ سُنَّةُ الأَوَّلِينَ فِي الَّذِينَ خَلَوْا مِنْ قَبْلِ أَنَّهُ لَا يُقْبَلَ الْإِيمَانُ عِنْدَ نُزُولِ الْعَذَابِ.