The Messenger of Allah ﷺ, while still in Mecca, said to the Muslims, "I have been shown the place of your migration. I was shown a salt-flat with palm trees between two stretches of black volcanic rock," meaning the two harras.So those who migrated set out for Medina when the Messenger of Allah ﷺ mentioned this, and some of those who had migrated to Abyssinia returned to Medina. Abu Bakr also prepared himself to migrate, but the Messenger of Allah ﷺ said to him, "Wait, for I hope that I will be granted permission."Abu Bakr asked, "Do you truly hope for that, may my father be ransomed for you?"He replied, "Yes."So Abu Bakr held himself back to accompany the Messenger of Allah ﷺ, and he fed two riding camels he had with leaves of the samur tree for four months.
قال رسول الله ﷺ وهو يومئذ بمكة للمسلمين: قد أريت دار هجرتكم أريت سبخة ذات نخل بين لابتين وهما الحرتان. فهاجر من هاجر قبل المدينة حين ذكر ذلك رسول الله ﷺ ورجع إلى المدينة بعض من كان هاجر إلى أرض الحبشة وتجهز أبو بكر مهاجرا. فقال له رسول الله ﷺ: على رسلك، فإني أرجو أن يؤذن لي قال أبو بكر: هل ترجو ذلك بأبي أنت؟ قال: نعم فحبس أبو بكر نفسه على رسول الله ﷺ ليصحبه، وعلف راحلتين كانتا عنده ورق السمر أربعة أشهر.
Bukhari narrated it in the chapter on suretyship (2297), from Yahya bin Bukayr, who said, Layth narrated to us, from Aqeel. Ibn Shihab said, Urwa bin Zubayr informed me, from Ayesha, and he mentioned it within a lengthy hadith, see, "Abu Bakr was among those who set out migrating to Abyssinia, then returned."As for his statement "the salt marsh," it refers to land that is damp and salty.