Al-Adab Al-Mufrad, Hadith 588 ⓘ
Ibn 'Abbas said, "If one mountain had acted tyrannically towards another mountain, the aggressor would have been pulverised."
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ: حَدَّثَنَا فِطْرٌ، عَنْ أَبِي يَحْيَى قَالَ: سَمِعْتُ مُجَاهِدًا، عَنِ ابْنِ عَبَّاسٍ قَالَ: لَوْ أَنَّ جَبَلاً بَغَى عَلَى جَبَلٍ لَدُكَّ الْبَاغِي.
also referenced under: Book 30, Hadith 51 (In-Book) & Book 30, Hadith 588 (English)