@Chelonian: FWIW, Kant imagined God's thinking to be not restricted by time, not his existence, i.e. when thinking of something, he thinks of it how it was, is, and ever will be at the same time. In other words, omniscience is implied by thinking that is not limited to time

@PhilipKlöcking Thank you, I didn't know that. Seems that at least some prominent theologians today (William Lane Craig, J.P. Moreland) describe the Christian god as actually being "outside of time". I don't know how popular this view is in the philosophical corners of Christianity today.