He claims that he swore allegiance to me with his hand but did not swear with his heart.1 So he does admit allegiance. As regards his claiming it otherwise than with his heart he should come forward with a clear argument for it. Otherwise, he should return to wherefrom he has gone out.2
(1) Al-Mufid, al-Jamal, 175, from (2)
(2) al-Waqidi, al-Jamal.
But this excuse is like that of the one who reverts to apostasy after adopting Islam and to avoid penalty may say that he had accepted Islam only by the tongue, not in the heart. Obviously, such an excuse cannot be heard, nor can avoid punishment by this argument. If az-Zubayr suspected that `Uthman was slain at Amir al-mu'minin's insistence, this suspicion should have existed when he was taking oath for obedience and stretching his hand for allegiance, not now that his expectations were getting frustrated and hopes had started dawning from somewhere else.