Some people have a generic concept of God. They believe there is a divine being or higher power; but they do not specify that God is the Creator of all things, or even more specifically and to the point that He is their Creator. There is a principle of studying the Bible called the first mention principle. This states that the first mention of a doctrine in the Bible should guide our interpretation of all further references of that doctrine. What is the first thing the Bible says about God? It is that He is the Creator (Gen 1:1). Before it tells us that He is holy, just, merciful, loving or anything else, it tells us He is the Creator. Why is this first? It is because everything else the Bible shows us about God is based on that fact. We cannot correctly understand anything else about our relationship with God without understanding He created us. Why does He judge us? It is because He is our Creator? Why did He become our Savior? It is because He created us and took responsibility for His creation even though sin was not His fault. Jesus Christ is the Creator who became one of His own creation to save us (Jn 1:1-18, Col 1:16).
When Peter preached on the day of Pentecost in Acts 2, he was speaking to a predominantly Jewish audience who was familiar with the scriptures. That dictated the content of what he preached. When Paul spoke to the Athenians in Acts 17, the content of his message was very different because his audience had no knowledge of the true God or the Bible. The first thing he told them to introduce God was that He is the Creator (Acts 17:24-31). He continued by explaining that God created us with the intention of having relationship with us as our Father. We can understand His eternal power and Godhead through creation (Rom 1:20). So we can only properly understand who God, and who He is to us by believing He created us, and not just generally. He created each and every one of us as unique and special. We are all the offspring of God by creation. God originally created everything good, but man sinned and brought the curse (Gen 1-3). Yet God so loved us that He showed mercy, and invites us to be born again so we can be the children of God twice over (Jn 3:1-7). The designer knows how creation ought to work. He gave us an instruction book to follow called the Bible. Sin is deviation from the manufacturer's instructions. That is why it damages and eventually destroys us. Sin is not part of our specifications. We can only function properly when we operate the way God made us to.
The doctrine of God being our Creator is probably the most attacked part of the Bible today, and it is the supposed intellectuals that are raising this attack through the religion of evolution. Evolution is not science. It is a belief which makes it a religion. It is not a modern religion either. It has been part of paganism for millennia. Evolution does not explain the origin of life, matter, energy, information, or laws. The Biblical account of creation does. So why is there such opposition to the idea the God created us? It is because when we acknowledge the Creator, we acknowledge His authority over us to rule us and to hold us accountable in judgment. Romans 1:18-32 shows us they know God is Creator and Judge but they suppress the truth in unrighteousness and deny Him. So in that sense there is no such thing as an atheist, only a denier. The enemy of our soul does not want us to understand that God created us so we could have relationship with Him and that we are accountable to Him. The enemy also does not want us to realize that the Creator knows how to fix His creation when it is damaged. He can heal us spiritually, emotionally, and physically. He took the curse of sin on the cross. Knowing our Creator gives us access to all He is to us, and all He does for us.