Book of Enoch (1 Enoch) 55:2
And He sware by His great name: ‘Henceforth I will not do so to all who dwell on the earth, and I will set a sign in the heaven: and this shall be a pledge of good faith between Me and them for ever, so long as heaven is above the earth. And this is in accordance with My command.
Background and history of Book of Enoch (1 Enoch), and issues with this book.
R. H. Charles, The Book of Enoch (London: SPCK, 1917), public domain. The verse text is the English Wikisource transcription of that translation. Charles’s editorial signs are kept. He rearranges some verses in chapters 5, 39, 90, 91, and 106, so those chapters are not a straight 1, 2, 3 sequence.