Alternative sources for this sermon
(see Bibliography for details of these texts)
Praise be to Allah from whose view one sky does not conceal another sky nor one earth another earth.
A part of the same sermon
About the Consultative Committee after the death of `Umar ibn al-Khattab
Someone  said to me, "O' son of Abi Talib, you are eager for the caliphate." Then I told him:
"Rather, you are, by Allah, more greedy, although more remote, while I am more suited as well as nearer. I have demanded it as my right, while you are intervening between me and it, and you are turning my face from it." When I knocked at his ears with arguments among the crowd of those present he was startled as if he was stunned not knowing what reply to give me about it.
O' my Allah! I seek Thy succour against the Quraysh and those who are assisting them, because they are denying me (the rights of) kinship, have lowered my high position, and are united in opposing me in the matter (of the caliphate) which is my right, and then they said, "Know that the rightful thing is that you have it and also that you may leave it." 
A part of the same sermon
Describing the people of Jamal
They (Talhah, az-Zubayr and their supporters) came out dragging the wife of the Messenger of Allah (the peace and blessing of Allah be upon him and his descendants) just as a maidslave is dragged for sale. They took her to Basrah where those two (Talhah and az-Zubayr) put their own women in their houses but exposed the wife of the Messenger of Allah to themselves and to others in the army in which there was not a single individual who had not offered me his obedience and sworn to me allegiance quite obediently, without any compulsion.
Here in Basrah they approached my governor and treasurers of the public treasury and its other inhabitants. They killed some of them in captivity and others by treachery. By Allah, even if they had wilfully killed only one individual from among the Muslims without any fault, it would have been lawful for me to kill the whole of this army because they were present in it but did not disagree with it nor prevented it by tongue or hand, not to say that they killed from among the Muslims a number equal to that with which they had marched on them.
Footnotes by translator:
.On the occasion of the Consultative Committee Sa`d ibn Abi Waqqas repeated to Amir al-mu'minin what Caliph `Umar had said in his last hours namely that "O' `Ali, you are very greedy for the position of caliphate," and `Ali replied that, "He who demands his own right cannot be called greedy; rather greedy is he who prevents the securing of the right and tries to grab it despite being unfit for it."
There is no doubt that Amir al-mu'minin considered the Caliphate to be his right, and demanded his right. The demand for a right does not dispel a right so that it may be put forth as an excuse for not assigning him the caliphate, and the demand may be held as a mark of greed. Even if it was greed, who was not involved in this greed? Was not the pull between the muhajirun and the ansar the mutual struggle between the members of the Consultative Committee and the mischief mongering of Talhah and az-Zubayr the product of this very greed. If Amir al-mu'minin had been greedy for this position, he would have stood for it, closing his eyes to the consequences and results, when `Abbas (uncle of the Prophet) and Abu Sufyan pressed him for (accepting) allegiance, and when, after the third Caliph people thronged to him for (swearing) allegiance, he should have accepted their offer without paying any attention to the deteriorated conditions. But at no time did Amir al-mu'minin take any step which could prove that he wanted the Caliphate for the sake of caliphate, but rather his demand for the caliphate was only with the object that its features should not be altered and the religion should not become the victim of others' desires, not that he should enjoy the pleasures of life which could be attributed to greed.
.Explaining the meaning, Ibn Abi'l-Hadid writes that Amir al-mu'minin's intention was to say:
They (the Quraysh and those who are assisting them) were not only content to keep me away from my right over the caliphate which they have usurped (from me), but rather claimed that it was their right whether to give it to me or prevent me from the same; and that I have no right to argue with them.
Furthermore, the intention (of Amir al-mu'minin) is that:
If they had not said that it is right to keep away from the caliphate, it would have been easy to endure it because this would have, at least, showed their admitting my right although they were not prepared to concede it. (Sharh Nahj al-balaghah, vol. 9, p. 306)