Yes, September I know the song well. It has always been accepted as referring to the Silver Chalice, that having it's origin of being the cup that Christ drank from with the apostles at the Last Supper.

It refers to life, for sure. But it has also come to refer to Christ Himself, those who drink regular water will thirst again , but those who drink of the cup of life = Christ, will never thirst (for life) again.

There are many net references you can look up... careful though because as it the way of all things in the world, the dark forces take good and use them for evil.

Please research anything I suggest before believing...