choose your medicine wisely
Krishna is living everywhere, that is the vision of the higher devotees. Actually He's living, but still, because we are in the lower condition, we should know that here is Krishna in the temple. Krishna is everywhere, but for us, because we have no such vision to see Krishna anywhere and everywhere, therefore we should come here in the temple and see Krishna, "Here is Krishna. Krishna has kindly appeared here in a manner in which I can see Him. That is Krishna's mercy." That is temple.
-Srila Prabhupada (Los Angeles, April 29, 1973)