Hasan on Quran: The Quran is a personal letter from Allah

Al-Nawawi reported: Al-Hasan ibn Ali, may Allah be pleased with him, said, “Verily, those before you viewed the Quran as letters from their Lord, such that they would contemplate it by night and yearn for it by day.”

Source: al-Tibyān fī Ādāb Ḥamalat al-Qur’ān 1/54

عن النووي وعن الحسن بن علي رضي الله عنه قال إنَّ مَنْ كان قَبْلَكُمْ رأوا القرآنَ رسائلَ مِنْ ربِّهِمْ فكانوا يتدبَّرونها بالليل ويَتَفَقَّدُونَها في النهار

1/54 التبيان في آداب حملة القرآن