Do not you see that Allah sends down from the sky water, then We bring forth therewith fruits (of) various [their] colors? And in the mountains (are) tracts, white and red (of) various [their] colors, and intensely black.
Is there anything more direct in the Qur'an or Ahadith?
There is almost no mention of rainbows in Islamic text, save for two hadiths attributed to Ibn 'Abbas in Al-Adab Al-Mufrad 33/14, with one classified as sahih (authentic) as below, and classified as da'īf (weak):
Ibn 'Abbas said, "The rainbow is security for the people of the earth that they will not be drowned. The Milky Way is the door of the heavens and forms a furrow through it."
Upon the authority of Ibn Abbaas – Radhiyallahu ‘Anhumaa – who said: “The rainbow is a safeguard for the inhabitants of the earth that they will not be drowned (as a form of destruction as in the time of Nooh) and the Milky Way is the door of the heavens and the splitting of the heavens will begin from it (i.e on the day of Judgement)”
(Collected by Imaamul Bukhaari in his Adabul Mufrad 767/590)
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