Thomas Aquinas argues that we can demontrate the existance of God in five differend ways. The Second of the five differentbways is known as Argument from Efficient Causes:
Where We perceive a series of efficient causes of things in the world and Nothing exists prior to itself.Therefore nothing [in the world of things we perceive] is the efficient cause of itself.If a previous efficient cause does not exist, neither does the thing that results (the effect),so if the first thing in a series does not exist, nothing in the series exists and If the series of efficient causes extends ad infinitum into the past, for then there would be no things existing now.This is plainly false (i.e., there are things existing now that came about through efficient causes). Therefore efficient causes do not extend ad infinitum into the past. Hence its necessary to admit a first efficient cause, to which everyone gives the name of God.