I do believe that every person we come across is a "Angelic Messenger" of sorts, even though we may not recognise that fact at that time. As is written in the above poem, "somebody out of nowhere, proved to be a friend indeed" and also "For God has many messengers, we fail to recognise." But that is human nature, I guess and hope that Sai gives us all the wisdom to see and recognise His ways.
You have posted a very good poem with deep meaning.