Very good Smedley. Now where does scripture tell men to repeat this Hail Mary for their own salvation? Or does it? Do you have to be told everything in the Bible specifically?
In that case, where are the prayers you yourself say? Are they word-for-word in the Bible?
You are not told exactly what to say, but God does ordain in His Word the different things you are to do in worship. Hail Mary's are not involved and any attempt at saying they are ordained in Scripture AT ALL is extremely dumb and full of the devil.