Addressing a Common Misconception: God's Creation vs God's Children

If I think back to the not so distant past, I can remember sitting in SAT review classes discussing the fact that all BMW's are cars, but not all cars are BMW's. Along the same lines as this would be a concept that I only recently considered, which is the fact that we are all God's creation, but we are not all God's children. Some might think I'm being overly picky, but the distinction is necessary.
Looking back at Genesis 1:27, we find that it states, "So God created man in his own image, in the image of God he created him; male and female he created them." This statement proves that God created each and every one of us. Those unable to accept this as fact are those who do not have the Holy Spirit residing within them, and thus, are lacking the necessary faith to believe, as mentioned in Hebrews 11:3 ~ "By faith we understand that the universe was created by the Word of God, so that what is seen was not made out of things that are visible." This lack of faith characterizes the unbelievers of the world, while being born of the Spirit is what distinguishes the believers, who are God's children.
Upon close analysis of Romans 8:5-8, there's a clear distinction between those who live by the flesh and those who live by the Spirit. Each and every person is born into a fallen world and has a sin nature that is opposed to all things holy. In that sense, all of Creation is on equal footing as we all fall short of God's righteousness. It is not until we are born again in the Spirit, as Jesus stated in John 3:3-6 that we are set apart for the Kingdom of God. It is only by God's grace that we are saved and able to be considered His children (Ephesians 2:1-10). Every Christian believer, therefore, is saved by God's grace and believes that Jesus is their Savior. Then, and only then, are they considered children of God and not just part of God's creation. John 1:12 clearly states, "But to all who did not receive him who believed in his name he gave the right to become children of God."
The most significant characteristic that makes it evident that someone is a believer in Christ, rather than an unbeliever is the Holy Spirit. Those individuals who repent of their sins and accept Christ in their hearts as Lord and Savior have the Holy Spirit dwelling within them. The Holy Spirit helps these individuals live according to the Spirit rather than the flesh, setting them apart as the true children of God. Proof of this is written in Romans 8:14, which says, "For all who are led by the Spirit of God are sons of God." This is of noted importance because Romans 8:16 reiterates this point with different wording by saying, "The Spirit himself bears witness with our spirit that we are children of God."
Many might claim to be Christians, but if there is no sanctifying proof of the Holy Spirit doing a work in their lives, they might be making false claims. Only those who accept Jesus as their Savior and through the help of the Holy Spirit try to obey God's Word are those who can be considered God's children and set apart for the kingdom of heaven.