His will shortly before his death
Nahj al-Balāgha|Volume 1|Book 2|Chapter 23
وَاللهِ مَا فَجَأَنِي مِنَ الْمَوْتِ وَارِدٌ كَرِهْتُهُ، وَلَا طَالِعٌ أَنْكَرْتُهُ، وَمَا كُنْتُ إِلَّا كَقَارِب وَرَدَ، وَطَالِب وَجَدَ، ﴿وَمَا عِندَ اللهِ خَيْرٌ لِّلْأَبْرَارِ﴾
By Allāh, this sudden death is not an event that I dislike, nor is it an accident that I hate. I am just like a night traveller who reaches the spring (in the morning) or like or seeker who secures (his aim): And whatever is with Allāh is the best for the righteous ones. (Qur’ān, 3:198)