Hadith 5842
وَزَادَ الْبُخَارِيُّ: حَتَّى حَزِنَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ-فِيمَا بَلَغَنَا-حُزْنًا غَدَا مِنْهُ مرَارًا كي يتردَّى منْ رؤوسِ شَوَاهِقِ الْجَبَلِ فَكُلَّمَا أَوْفَى بِذِرْوَةِ جَبَلٍ لِكَيْ يُلْقِيَ نَفْسَهُ مِنْهُ تَبَدَّى لَهُ جِبْرِيلُ فَقَالَ: يَا مُحَمَّدُ إِنَّكَ رَسُولُ اللَّهِ حَقًّا. فَيَسْكُنُ لذلكَ جأشُه وتقرُّ نفسُه
Bukhari added: so that the Prophet was grieved, as we have heard, and on that account went out in the morning several times to throw himself down from the heights of the mountain; but as often as he reached the summit of a mountain to throw himself from it, Gabriel appeared to him and said, "Muhammad, you are truly God's messenger." On that account his turmoil would then quieten and he would feel at ease.