From a friend who is a Christian and a physicist:

Time is just another dimension, but not quite the same as the space dimensions. There is even speculation about other time dimensions other than the one we experience. Of course there can be no time, just as there can be no fourth space dimension etc. Many physicists believe that in fact there are currently 17 space dimensions, but we live (mainly) in 3 of them. The physics suggests that the number of dimensions is quite arbitrary and a universe *could* be created with any number, but most of them would be rather interesting places as far as human life is concerned. Three space dimensions seems to give just enough complexity for chemistry to work well, but add more and it gets very complicated very quickly. Ever seen the screensaver of the rotating 4-dimensional cube? Two space dimensions makes everything too simple. Obviously if there was no time dimension, things would be very boring indeed.

BTW dimensions don’t have to be very large, and may curl back on themselves. Time may not, as you say, have a beginning or an end, and it may curl back on itself every now and then, so that history just reruns itself. Just like if you head in a straight line anywhere on the earth, you will come back to where you started and keep going in circles for ever. Red Dwarf did a brilliant episode on this, because as time runs backwards, causality is reversed so that the effects come before the causes! It was probably the funniest episode of all their series.

The universe … may have been created from nothing, but the energy needed had to come from somewhere. So there must be an ‘outside’, even if we have no idea what it might be like. Physicists often refer to it as “quantum froth”, but as no-one has any idea how to step outside (other than to jump into a black hole, but then it will take a long time to exit, it will get rather hot inside and you will be compressed into something much smaller than an electron), its just speculation.

To the assertion that ‘Time is a concept, not a substance. ‘

He replied:

No, time is not a concept, it is a dimension. Try reading The Shorter History of Time.

[I believe that God created the universe}.