We are actually discussing this very subject in my philosophy class...

according to Aquinas’ First Cause Argument Summa Theologica, Question II, Third Article, it states that:

"In the world of sensible things we find there is an order of efficient causes. There is no case known (neither is it, indeed, possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible. Now in efficient causes it is not possible to go on to infinity, because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate cause be several , or one only. Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate nor any intermediate cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there by an ultimate effect, nor any intermediate efficient causes; all of which is plainly false. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name God."

in class we broke down the premises and conclusions:
1. In the world of physical things there is an order of physical causes followed by effects.
2. It’s impossible for a thing to cause itself. (Conclusion)
3. For, if a thing caused itself, it would exist before it existed.
4. It’s impossible for a thing to exist before it exists.
5. The order of physical causes followed by effects cannot go back infinitely. (Conclusion)
6. Because in the order of physical causes followed by effects, each step exists only if the previous step exists.
7. If there is no cause, there is no effect.
8. Therefore, if there are no first causes in an order of physical causes followed by effects, there are no subsequent physical effects. (Conclusion)
9. There are subsequent physical causes followed by effects.
10. Therefore there is a first cause. (Conclusion)
11. Everyone calls the first cause God.
12. God exists. (Conclusion)

which still brings up the question(s) of: Was there a first cause of everything or is there an infinite series of causes?

I would also delve into William Paley's Natural Theology but it doesn't really pertain to time, but more on physical existence and its natural purpose and who made what; essentially it argues that God created everything therefore God exists