Language:
كتاب مناقب الأنصار
63  
Merits of the Helpers in Madinah (Ansaar)
(42)
Chapter: Al-Mi’raj
(42)
باب الْمِعْرَاجِ
Sahih al-Bukhari 3888

Narrated Ibn `Abbas:

Regarding the Statement of Allah" "And We granted the vision (Ascension to the heavens) which We made you see (as an actual eye witness) was only made as a trial for the people." (17.60) Ibn `Abbas added: The sights which Allah's Messenger (ﷺ) was shown on the Night Journey when he was taken to Bait-ulMaqdis (i.e. Jerusalem) were actual sights, (not dreams). And the Cursed Tree (mentioned) in the Qur'an is the tree of Zaqqum (itself) .

حَدَّثَنَا الْحُمَيْدِيُّ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا عَمْرٌو، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ فِي قَوْلِهِ تَعَالَى ‏{‏وَمَا جَعَلْنَا الرُّؤْيَا الَّتِي أَرَيْنَاكَ إِلاَّ فِتْنَةً لِلنَّاسِ‏}‏ قَالَ هِيَ رُؤْيَا عَيْنٍ، أُرِيَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم لَيْلَةَ أُسْرِيَ بِهِ إِلَى بَيْتِ الْمَقْدِسِ‏.‏ قَالَ وَالشَّجَرَةَ الْمَلْعُونَةَ فِي الْقُرْآنِ قَالَ هِيَ شَجَرَةُ الزَّقُّومِ‏.‏
Reference : Sahih al-Bukhari 3888
In-book reference : Book 63, Hadith 113
USC-MSA web (English) reference : Vol. 5, Book 58, Hadith 228
  (deprecated numbering scheme)