Al-Adab Al-Mufrad, Book 33, Hadith 765 (English) ⓘ
Ibn Abbas said, "The Milky Way is one of the gates of the heavens. The rainbow is security from being destroyed by flood after the people of Nuh, peace be upon him."
حَدَّثَنَا الْحَسَنُ بْنُ عُمَرَ، قَالَ: حَدَّثَنَا عَبْدُ الْوَارِثِ، عَنْ عَلِيِّ بْنِ زَيْدٍ قَالَ: حَدَّثَنِي يُوسُفُ بْنُ مِهْرَانَ، عَنِ ابْنِ عَبَّاسٍ قَالَ: الْمَجَرَّةُ: بَابٌ مِنْ أَبْوَابِ السَّمَاءِ، وَأَمَّا قَوْسُ قُزَحٍ: فَأَمَانٌ مِنَ الْغَرَقِ بَعْدَ قَوْمِ نُوحٍ عَلَيْهِ السَّلامُ.
also referenced under: Hadith 765 (Reference) & Book 33, Hadith 12 (In-Book)