"Die Quantenmechanik ist sehr achtung-gebietend. Aber eine innere Stimme sagt mir, daß das doch nicht der wahre Jakob ist. Die Theorie liefert viel, aber dem Geheimnis des Alten bringt sie uns kaum näher. Jedenfalls bin ich überzeugt, daß der nicht würfelt."
There are a number of different translations, but one is:
Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the "old one." I, at any rate, am convinced that He does not throw dice.
It is relatively easy to understand both the context and meaning of what Einstein said, especially if you read his numerous other works. The objection to some of the key underpinnings of Quantum Mechanics was something he mentioned a number of times.
They key here is that you can explore and understand what Einstein was talking about without digging deep into the meaning of a god, or his view of religion. The concepts of Quantum Mechanics are complicated enough to keep any undergrad or grad student busy for a lifetime.