Can you explain some common arguments for the existence of the Christian God?

There are many different arguments that are used as a way of showing that the Christian God exists. I will explain two common ones that were developed by St Thomas Aquinas: his cosmological and teleological arguments. Firstly, Aquinas's cosmological, or 'first cause', argument, states that everything in the universe has a cause. However, this chain of cause and effect cannot go back for infinity; there must have been a first cause that initiated this chain of events. This first cause is what Christians call God. This Being is necessary, as the universe would not have come into existence without it. Furthermore, this Being transcends space and time, for it must have existed outside these realms in order to be the cause of their existence. Secondly, his teleological, or 'design', argument rests on the observation of design and order throughout the universe. For example, the Golden ratio that is often present in nature. This design is too intricate and this order is too considered for one to be able to accept that the universe came about by chance. There must have been a designer and this designer is what Christians call God. William Paley used an analogy of a watch and a watchmaker to demonstrate this point. If one came across a watch lying on a rock, upon observing its intricate design one would assume that a watchmaker had created it, rather than suppose that it had just come into existence by pure chance. Similarly a being intended to create the universe, and the universe's complex design is evidence of this.