What my teacher (Shaykh Al-Mufid) narrated to me, may Allah سبحانه وتعالى support him, from Abu al-Qasim Ja’far ibn Muhammad, from Muhammad ibn Ya’qub, from a group of our companions, from Ahmad ibn Muhammad, from al-Abbas ibn Amir al-Qasbani, from Abdullah ibn Bukayr, from his father, who said: Abu Abdullah عليه السلام said to me: "If you are certain that you have performed ablution, then do not renew your ablution unless you are certain that you have invalidated it."