Einstein uses his concept of God more often than a Catholic priest. Once I asked him:
'Tomorrow is Sunday. Do you want me to come to you, so we can work?'
'Why not?'
'Because I thought perhaps you would like to rest on Sunday.'
Einstein settled the question by saying with a loud laugh: 'God does not rest on Sunday either.'

It is odd to think that there is a word for something which, strictly speaking, does not exist, namely, 'rest'. We distinguish between living and dead matter; between moving bodies and bodies at rest. This is a primitive point of view. What seems dead, a stone or the proverbial 'door-nail', say, is actually forever in motion. We have merely become accustomed to judge by outward appearances; by the deceptive impressions we get through our senses.

Rest is not idleness, and to lie sometimes on the grass under trees on a summer's day, listening to the murmur of the water, or watching the clouds float across the sky, is by no means a waste of time.