Ayn-al-Qużat in Arabic means “the pearl of the judges”: Ayn means the eye, implying something very valuable, and Qozat is the plural of Qadi, which means judge.
He was born in Hamedan and his ancestors were of Hamedan judges. He was a disciple of Ahmad Ghazali and devoted of Hallaj. He became a famous scholar at early ages, and by the time he was thirty he was chosen judge. Along with Abu Hamed Al-Ghazali, he is one of the founders of doctrinal Sufism. According to some accounts, he was briefly a pupil of Omar Khayyam. Upon his return from pilgrimage, Khayyam likely stayed in Hamadan for some time. It is possible that during his stay he became tutor to the young Ain al-Quzat. However, Aminrazavi (2007) believes that from the figures who may have studied with Khayyam Ain al-Quzat is the least likely and that arguing their association is wishful thinking by those who like to view Khayyam as a Sufi. Unlike most of the Sufis who have lived as respected and revered members of their communities, he fell afoul of the Seljuk rulers and was accused of heresy and executed, either by crucifixion or burning.
Ayn al-Quzat along with Mansur al-Hallaj and Shahab al-Din Suhrawardi are known as the three martyrs of Sufism.
The most significant works of Ayn al-Qożāt are Tamhīdāt (Preludes) and Zubdat al-ḥaqāʾiq fī kašf al-ḵalāʾeq (The Essence of Truth). Both books are masterpieces of Sufi literature and have mystical and philosophical significance. Ayn al-Qożāt Hamadānī quoted a few verses apparently in his own Iranian dialect (where it is called fahlavī; bayt-e pahlavī in a manuscript variant).
A famous quatrain is said to be his:
ما مرگ وشهادت از خدا خواسته ايم
I want death and martyrdom from God
This quatrain refers to his execution by Caliph’s order.