That same night Hazrat Jibrael (A) appeared to Rasulullah (SM), telling him of the whole plan, also telling him to let Hazrat Ali sleep on his bed that night while he himself should on that night begin thejourney of the Hijrat to Madinah.
Therefore in response to that revelation in spite of the watchfulness of the young men of Quraish he managed to have walked through them, reciting some verses from Surah Yaseen : "And We covered them up so that they cannot see."
He also picked up a handful of dust and threw it towards their heads as he left them and proceeded to the house of Abu Bakr and there gave him the news to accompany him on this journey and then set forth in the direction of Madinah.
Thisjourney took place on a Monday in Rabee-il-Awwal in the 13th year of the mission and this important journey in all its miraculous happenings is recorded in detail in the Hadith and the fact that Abu Bakr was his companion is mentioned in the Qur'an thus:
"He had no more than one companion,
They two were in the cave
And he said to (Abu Bakr) his companion:
"Have no grief, for Allah is with us " (9:39)
At that moment Rasulullah (SM) addressing Abu Bakr (Ra) did not say: "Have no fear" but he said: "Laa Tahzan" "Have no grief or sorrow". The reason is that fear is something where one fears the harmful effects and in this case it is as if the Qur'an states that Abu Bakr had no fear for his life or himself but his great fear was over the arrest of Rasulullah (SM) and the sorrow it would cause him if he was to fall into die hands of the unbelievers. Rasulullah (SM) realized this and instead of Laa Takhaf he said 'Laa Tahzan', and by adding that "Allah is with us" he actually put a stamp upon their companionship and its acceptance by Allah (SWT).
Even if people with hatred, enmity and irreligion should try their utmost to disprove and condemn the companionship of Abu Bakr with Rasulullah (SM) and even if they utter whatever they wish to utter, they will be unable to remove or destroy the companionship of Abu Bakr (Ra). And even if they should spend all the strength of the universe to remove it, it is not to be removed. "That is the favour of Allah (SWT) which He grants to whomsoever He wishes."