Because to avoid infinite regression, there has to be a first uncaused cause.
Also, at the risk of abuse, I believe the bible, and an infinite God is central to my belief.
Why do I believe the bible?
Wow!
I'm setting myself up for a tirade of mocking but I'll try to answer to your satisfaction, but later if you ask.
There is no universal law of cause and effect. Quantum Mechanics demonstrates the fundamental nature of reality is random.
If you presume there is a law of cause and effect then you are faced with a choice between infinite regression or a breaking of the "universal" law by having something without a cause. Either way it is clearly nonsense.
Moreover, having a god as the original cause requires that the most complex thing there could ever be has to be the thing without a cause and it must exist without anywhere to exist in. Crazy.
Science shows us that the first thing is a formless ball of pure energy that burst into existence through random fluctuations in the Void. From this comes all the complexity we see by following a small number of well established universal relationships for which there have been no observed exceptions.
Theland premise for everything is to set an rule that he insists science is bound by (even when the science show it is not) then call an exemption for God.
Universal cause and effect for everything except God.
Evolution is wrong because nobody has ever seen an animal turn into another species (won't accept speciation in microorganisms). Of course nobody has ever seen an any organism created from nothing as his god is supposed to have done but that OK.
Nobody has ever seen his god either but we are to accept it exists because some ignorant Bronze Age men said so an wrote it in a book that is full of contradictions.
Give us a break Theland and start answering the questions we ask you before you repeat the nonsense we have already debunked many times.
Causality does not exist 'outside' of or apart from that within which it takes place. Causality, like the codependent aspects of time and space, acquires meaning only within the context of the universe from which it became manifest and to which it applies. The universe had no cause or beginning, it is the stage upon which all things within it (including time, space and indeed consciousness itself) begin, take place, unfold and acquire form.
Theland; if there is a first cause, how do you know that it is a male, beneficent, loving, demanding......? If you say because it's in the Bible, I would simply ask why do you keep on seeking to reason with us and persuade us by logic? Why not just accept your book and give us all a rest?
1 Peter 3:15
But in your hearts revere Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect
Theland 21;40
I have my beliefs and you have yours.
That's it.