Thats an interest question
If you don't believe in god then why live a like a good person whats the point? Then why dont you commit evil then refuse to believe in any consequences for your actions.
God/Allah is great and part of his greatness is that he gives us chance after chance to believe and we forego every chance.
Where did we learn good character?
Was it from ourselves? Well this is impossible before the age of enlightenment of the west (because the east was alight at this time) there was a period of darkness and a lull in learning. part of this learning was charaters of the prophets.
For example it is well known that Jesus upon him peace was a forgiving prophet and spread peace. This character was embraced by thousands of people. So this proves that a person on their own cannot come up with good character because he needs an example, right?
Like free kick expert can show people tricks how to take a free kick because he knows - look at david beckham.
So who is seeming someone human to educate humans that they can reach good character? That has to be from a greater authority that is God.
If you believe that everything is created and it has a dependant lifespan then there must be some power which is independant bring them from non existance into life then into death.
So if things are coming from non-existance into life then into death who is taking this created thing from one stage to the next? You must conclude that is God/Allah. The ever living, the uncreated, cause of all causes, right?
There was once a man who argued with Ali ibn Abu talib about the afterlife. The man refused to believe in it. Ali said, "If you are right and I am wrong. I am okay and you are okay. But if I am right then I am still okay but you are not."
I don't know about you but I am not a betting man. I like to have things ready before I die and part of that is belief in God/Allah and his prophets including the final messenger Muhammad (peace and blessings of God be upon him).