His saying, the Almighty, the Mentioned: "Indeed, those who disbelieved after their belief, then increased in disbelief" (Quran 3:90). Al-Hasan said: They are the People of the Scripture; they were believers, then they disbelieved, then they increased in disbelief; meaning: they died in their state of disbelief.
It means: Allah will not accept their belief that preceded that, [if they die] in their state of disbelief, "and it is they who are the lost ones."
قَوْله عز ذكره: ﴿إِنَّ الَّذِينَ كَفَرُوا بَعْدَ إِيمَانِهِمْ ثُمَّ ازْدَادُوا كفرا﴾ قَالَ الْحسن: هم أهل الْكتاب كَانُوا مُؤمنين، ثمَّ كفرُوا ثمَّ ازدادوا كفرا؛ أَي: مَاتُوا على كفرهم.
يَقُول: لن يقبل الله إِيمَانهم الَّذِي كَانَ قبل ذَلِك، [إِذا مَاتُوا] على كفرهم ﴿وَأُولَئِكَ هُمُ الضَّالُّونَ﴾
