Aeval - fantastic colours on that one - love the cloud formation too. 
It probably came about from a number of sources but the Bible also talks of red skies at night being ok and at morning - not so much. That combined with other later influences probably resulted in the variation of the saying that we have today.
Red sky at night shepherds delight is a saying that people said about the weather meaning that the weather in the morning would be great after a red sky at night. Red in the morning was considered shepherds warning as it meant rain was likely.
It was believed to be an old wives tale, but they have recently been able to explain it scientifically, that it is true more times than not
It probably came about from a number of sources but the Bible also talks of red skies at night being ok and at morning - not so much. That combined with other later influences probably resulted in the variation of the saying that we have today.






