Where Does The Saying 'Red Sky At Night...' Come From?

The proverb 'Red sky at night, shepherd's delight, red sky in the morning, shepherd's warning' is actually a very ancient proverb and it is likely that it has been repeated for many thousands of years.
It is mentioned (in a sense) in the bible.  In Matthew's Gospel of the New Testament, it is stated that 'When it is evening..it will be fair weather: for the sky is red.  And in the morning it will be foul weather for the sky is red'.

It is likely that our forefathers were as obsessed with the weather as we are today and so people who studied the weather began to notice that often the weather was fine if the sky had been red the night before.  And these reflections pre-date the bible's New Testament and so are at least two thousand years old.