From the Sayings of the Wise Concerning Seclusion

208 - Al-Ḥusayn said: Abū Bakr ibn Abī al-Dunyā said to us: Abū ʿAbd Allāh al-Bāhilī wrote to me, saying: Aḥmad ibn Muḥammad narrated to me: Yaḥyā ibn Saʿīd narrated to us, saying: Naṣr ibn Yaḥyā ibn Abī Kathīr—and he was among the wise—said: "We have not found anything more effective in Asceticism (Zuhd) regarding worldly life than the constancy of grief for the Hereafter in the heart of the servant. Whosoever has that firmly established in his heart, it comforts him with solitude, so he becomes comfortable with it and feels alienated from created beings; and that is when he experiences the sweetness of the love of seclusion flowing through his limbs just as water flows through the roots of a tree, so that its branches put forth leaves,