Plotinos: Complete Works, v. 2 In Chronological Order,...

The first Principle may indeed be conceived of as a spring (of water) which is its own origin, and which pours its water into many streams without itself becoming exhausted by what it yields, or even without running low, because the streams that it forms, before flowing away each in its own direction, and while knowing which direction it is to follow, yet mingles its waters with the spring.