Sermon (237): When Uthman sent a message to him through Abdullah Ibn Abbas that he should go to Yanbu, he said:

During the days when Uthman Ibn Affan was under siege, Abdullah Ibn Abbas came to Amirul Momineen (A.S.) with a letter from him, in which he wished him to move to his estate Yanbu, so that the name of Hazrat who is being called for the caliphate may be reduced. Uthman only wants to make me his water camel that sometimes moves forward and sometimes retreats with the dole. He sent the same message before that I should leave (Madinah) and after that he sent me to return. Now again they send word that I should go away (as far as was proper) I saved them, now I fear lest I should become sinful somewhere (by helping them).