This is the answer I gave when another member asked this question 10 days ago:
A source is an origin. It's where something comes from. For example, the source of a river is where it starts. The source of a problem is whatever or whoever caused the problem. A source of food, money and so on is the place where you can find these things.
A resource is something which is available and which we make use of. We can describe water, oil, minerals and suchlike as the earth's natural resources. If you are studying, you can think of books as resources. The money that someone has can be referred to as (financial) resources, while strength, courage, patience are a person's own natural resources.
In the most basic sense, 'resource' answers the question 'What?', while 'source' answers the question 'Where (from) ?'
The person for whom I wrote this answer did not even have the common courtesy to acknowledge it. I hope it helps you, anyway.