Abu Yusuf Yaqub bin Ishaq (802-858 A.D./ 186-244 A.H.) was a famous Iranian Shi'ite philologist and traditionist. Sikkait was the nickname of his father Ishaq who due to his excessive silence was nicknamed accordingly. Ibn Sikkait was born in Duraq in Khuzestan and later with his family went to Baghdad. He studied under famous scholars of his period like Abu Amru Shaybani, Farra, Ibn A'rabi, Asram and Nasran Khurasani. He soon become one of the famous scholars of his era like Ibn A'rabi and Abul Abbas Thalab and was considered as a distinguished philologist and eloquent orator.
Ibn Sikkait not only had outstanding activity in the fields of syntax and philology and played an important role in collecting and compiling Arabic poetry. He was also an ardent follower of the Sunnah of the Holy Prophet of Islam (S.A.W.A.) and was strictly bounded to his beliefs. In addition of collecting and compiling Arabic poetry he collected and narrated religious traditions also. Dhabi considered him as a very pious and religious person and he was martyred for his deep love and affection towards Holy Ahlul Bayt (A.S.). Najashi considers him as the close companion of Imam Muhammad Taqi (A.S.) and Imam Ali-un Naqi (A.S.) and quotes the traditions of Imam Muhammad Taqi (A.S.). narrated by him.
Many students gained vastly from his knowledge. Ibn Sikkait also recited poetry and Dhabi has extolled his poetry. All the sources has mentioned that he was martyred by Mutawakkil, the Abbasid caliph for his deep love for the Holy Ahlebayt (A.S.).
His printed works are as follows:-
1 - Islah al-Mantiq; 2 - Al-Azdad; 3 - Al-Alfaz: 4 - Al Qalb wal Abdal; some other manuscripts and works are also ascribed to him.