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."  

عَنِ ابْنِ عَبَّاسٍ قَالَ الْمَجَرَّةُ بَابٌ مِنْ أَبْوَابِ السَّمَاءِ وَأَمَّا قَوْسُ قُزَحٍ فَأَمَانٌ مِنَ الْغَرَقِ بَعْدَ قَوْمِ نُوحٍ عَلَيْهِ السَّلامُ