He is the author of the work titled al-Mukhtaṣar fī’l-Fiqh, written according to the madhhab of Imam Aḥmad b. Ḥanbal. This work was commented upon by Qāḍī Abū Yaʿlā b. Farrā and Shaykh Muwafaq al-Dīn b. Qudāmah al-Maqdisī.
ʿUmar b. Ḥusayn al-Ḥirāqī was among the foremost of the fuqahāʾ (jurists) and ʿābidīn (devout worshippers). He was a very virtuous and frequently worshipping person. Because great evils occurred in the city and the ṣaḥāba (the Companions) were insulted, he left Baghdad and emigrated elsewhere. He had also left his books in Baghdad. However, when the house where his books were kept was burned, all his works were destroyed. He himself went to Damascus and remained there until his death in that year. His grave is located in Bab al-Saghīr, near the graves of the martyrs, and it is visited.
In the section on ḥajj in his work al-Mukhtaṣar fī’l-Fiqh, he says: "The person going for ḥajj, when circumambulating the Kaʿba, comes to the place where the Ḥajar al-Aswad (the Black Stone) is located, and if it is in its place, kisses the Ḥajar al-Aswad." He said this because when he wrote this book, the Ḥajar al-Aswad had been taken by the Karmatians in the year 327 AH to the land of Spedip, and this blessed stone was only returned to its place in the year 337 AH. Indeed, this matter will be explained later when the occasion arises.
Al-Ḥāṭib al-Baghdādī narrated that Qāḍī Abū Yaʿlā told him:
"ʿUmar b. Ḥusayn al-Ḥirāqī had many works. He transmitted many reports related to the Ḥanbalī madhhab. However, these works and reports did not become known because he left Baghdad and emigrated elsewhere due to the great insults directed at the ṣaḥāba in the city, and he left his books in Baghdad. When the house where his books were kept was burned, his books also burned, and after him they did not spread outside Baghdad."
Al-Ḥāṭib al-Baghdādī also narrated that ʿUmar b. Ḥusayn al-Ḥirāqī said:
"I saw in a dream the Commander of the Faithful, Ḥazrat ʿAlī (may God be pleased with him). He said to me:
- How beautiful it is for the rich to show humility to the poor!
- O Commander of the Faithful, tell me more.
- Even more beautiful than that is for the poor to show pride towards the rich."
After saying this, Ḥazrat ʿAlī (r.a.) raised his hand. I saw written on his palm:
"You were dead before, then you were brought to life. Soon you will die again. Build a house for the eternal abode and leave a house in the mortal world."
Ibn Baṭṭah said: "ʿUmar b. Ḥusayn al-Ḥirāqī died in Damascus in the year 334 AH. I visited his grave. May Allah have mercy on him."