Sahih Bukhari
Merits of the Helpers in Madinah (Ansaar)
Volume: 005 / Book Number: 058 / Hadith Number: 228
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 Apostle 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 Quran is the tree of Zaqqum (itself) .