Al-Muhasibi was a phenomenal figure in the VIII-IX centuries who mastered several disciplines. especially fiqh and al-hadith as well as Sufism. Al-Muhasibi was born in Iraq in 781 AD (165 AH). His thoughts in the field of Sufism can be found in several of his monumental works. https://www.sahmbuffy.com/product-category/solar-hybrid-invertor/