A source is a place where you obtain something. A resource is something that you need. The source is where the resource comes from. Examples: If I needed water (the resource) I'd go to the well (the source). If I needed money (the resource) I'd go to the bank (the source).

"What's the difference between source and resource?" http://www.thefreedictionary.com/source http://www.thefreedictionary.com/resource You can see how the "re-" prefix works here: http://www.thefreedictionary.com/re-