Ayyūb Al-Sakhtiyānī reports that Abū Qilābah – Allāh have mercy on him – said:
Ibn ʿAbd Al-Barr, Jāmiʿ Bayān Al-ʿIlm, article 1279.
It is reported that the inscription on the ring of Ḥusayn b. ʿAlī – Allāh be pleased with them – read:
You know, so now act (علِمت فاعمل).
Op. cit. article 1280.