Alternative sources for this sermon
(see Bibliography for details of these texts)
In  this sermon Amir al-mu'minin has related his own condition after the Prophet's immigration till his meeting with him.I began following the path adopted by the Prophet and treading on the lines of his remembrance till I reached al-`Arj.
as-Sayyid ar-Radi says: Amir al-mu'minin's words "faata'u dhikrahu" constitute the highest forms of brevity and eloquence. He means to say that he was being given news about the Prophet from the commencement of his setting out till he reached this place, and he has expressed this sense in this wonderful expression.
Footnotes by translator:
.Since the commencement of prophethood, the Prophet remained in Mecca for thirteen years. For him, this period was of the severest oppression and destitution. The unbelievers of the Quraysh had closed all the doors of livelihood upon him, and had left no deficiency in inflicting hardships upon him, so much so that in order to take his life they began contriving how to do away with him. Forty of their nobles assembled in the hall of audience (Dar an-Nadwah) for consultation, and decided that one individual should be picked out from every tribe and they should jointly attack him. In this way, Banu Hashim would not dare to face all the tribes, and the matter would quieten down on the payment of blood price. To give a practical shape to this scheme, these people sat in ambush near the house of the Prophet on the night of the first of Rabi` al-awwal, so that when the prophet slept in his bed he would be attacked. On this side the preparation for killing him was complete, and on the other side Allah informed him of all the intrigues of the Quraysh unbelievers and commanded him to make `Ali (p.b.u.h.) sleep on his bed and himself to immigrate to Medina. The Prophet sent for `Ali (p.b.u.h.) and disclosing to him his plan, said: "Ali, you lie on my bed." Amir al-mu'minin enquired: "O' Messenger of Allah, will your life be saved by my sleeping here?" The Prophet said: "Yes." Hearing this Amir al-mu'minin performed a prostration in thanks-giving and, exposing himself fully to the danger, lay on the Prophet's bed while the Prophet left from the rear door. The Quraysh unbelievers were peeping and getting ready for the attack but Abu Lahab said: "It is not proper to attack in the night because there are women and children also in the house. When morning dawns you attack him, but keep watch during night that he should not move anywhere." Consequently, they kept their eyes on the bed throughout the night and soon, on the appearance of the dawn, proceeded forward stealthily. Hearing the sound of their footsteps, Amir al-mu'minin removed the covering from his face and stood up. The Quraysh gazed at him with stretched eyes as to whether it was an illusion or fact. After making sure that it was `Ali they enquired, "Where is Muhammad?" and `Ali replied, "Did you entrust him to me, that now you are asking me?" They had no reply to this. Men ran to chase him but found footprints only up to the cave of Thawr. Beyond that there were neither footprints nor any sign of hiding in the cave. They came back bewildered while the Prophet after staying in the cave for three days left for Medina. Amir al-mu'minin passed these three days in Mecca, returned to the people their properties lying in trust with the Prophet and set off towards Medina to join the Prophet. Upto al-`Arj which is a place between Mecca and Medina, he kept getting news about the Prophet and he continued his anxious march in his search till he met the Prophet at Quba on the twelfth of Rabi` al-awwal, and entered Medina with him. (at-Tabari, at-Tafsir, vol. 9, pp. 148-151; at-Tarikh, vol. 1, pp. 1232-1234; Ibn Sa`d, at-Tabaqat, vol. 1, Part 1, pp. 153-154; Ibn Hisham, as-Sirah, vol. 2, pp. 124-128; Ibn al-Athir, Usd al-ghabah, vol. 4, p. 25; al-Kamil, vol. 2, pp. 101-104; Ibn Kathir, at-Tafsir, vol. 2, pp. 302-303; at-Tarikh, vol. 3, pp. 180-181; Ibn Abi'l-Hadid, vol. 13, pp. 303-306; as-Suyuti, ad-Durr al-manthur, vol. 3, pp. 179-180; al-`Allamah al-Majlisi, Bihar al-anwar, vol. 19, pp. 28-103).