Sunan an-Nasa'i, Volume 2, Book 15, Hadith 1436 (DarusSalam) ⓘ
It was narrated from Ibn 'Abbas that: The Messenger of Allah set out from Makkah to Al-Madinah, fearing nothing but the Lord of the worlds, and praying two rak'ahs.
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا هُشَيْمٌ، عَنْ مَنْصُورِ بْنِ زَاذَانَ، عَنِ ابْنِ سِيرِينَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم خَرَجَ مِنْ مَكَّةَ إِلَى الْمَدِينَةِ لاَ يَخَافُ إِلاَّ رَبَّ الْعَالَمِينَ يُصَلِّي رَكْعَتَيْنِ .
also referenced under: Hadith 1435 (Reference) & Book 15, Hadith 3 (In-Book)