All mankind has a twitching, suspicion, hunch that God exists. We have to be taught or choose to disbelieve what is obvious to the soul. Our world, is one of creation and death and all things follow the same cycle. Even when an engineer designs and builds a car, he does so with a design life or a life with normal maintenance and care that will provide a vehicle that will within reason get you from point A to point B.
A professor of mechanical engineering once described a perfect design and used the lifecycle of a car to illustrate this. Cars, once designed for a 100,000 mile life would continue to provide reliable transportation with suggested maintenance, however, when the odometer rolls over to 99,9999 miles, the driver should quickly pull over and jump out because the next mile would be littered with the complete failure of every part and assembly which made up the car.
Everything we have and see is in a process of dying, stars, planets, and even mountains continue to wither away. If we build a wooden porch, we are plagued with a life of continual maintenance, painting and replacing damaged or rotting wood.
God originally created man and his world perfectly, God gave man all he needed and would provide all he needed, however, He also gave man a choice to willingly follow and obey His instructions and of course man disobeyed and brought that sin into creation, and with that came the death of things.
God is completely good and perfectly holy. Since the nature of choice provides a minimum of two outcomes the initial choice was for good vs evil. Man chose to disobey and with that came the consequences which was death. God knows man cannot obey His law perfectly so His plan B for us was a substitute for us which is Christ. Thank goodness He did not chose just to discard us and destroy our chances for redemption.
Today, with all our magnificent accomplishments such as space travel, massive structures that are constructed with steel and concrete and even now man is attempting to modify life forms with genetic engineering and even create new creatures by editing genetic code. We have accomplished so much that we have minimized God in the mind of man. Some may even consider Him to be the silent creator of all, but we (man) can improve it with our vast knowledge and intellect. Man is mimicking the 5 I WILLS's which brought down Satan.
This is not the God described in the Bible but a god created for mankind to play with. God is not the silent partner which serves our needs and desires, but rather He is the Creator of All Things.
God delivered his message to us through the inspiration of men, which wrote the words that He pressed on their minds and hearts into the form of the many books of the Bible. In this book He exposes and details His character and from the beginning to the end is one consistent message of what was to come. There would be a substitution of payment (our death) for disobedience and that substitution would be Christ.
To reject that offer would be the equivalent of standing before a Judge having been accused of speeding and after the Judge had delivered his judgment of a huge fine, the Judge steps down from the bench and pulls out his wallet offering to pay the fine for the speeder. Taking lightly God's substitution of Jesus for payment of our sins would be the equivalent of the speeder laughing at the Judge and rejecting his offer. Of course, I bet if this actually ever happened to a Judge in the US, the speeder is probably serving a life term!
The awesome and amazing part of the Christian message is that it is so immensely simple what God has done. One does not have to have a doctorate in Theology, studied the Bible for decades or even present oneself to work off the debt in a life of servitude. One does not have to memorize scripture, kill a thousand fatted calfs or sacrifice his firstborn on an alter. All that is required is to admit we cannot work enough, pray enough, be good enough or anything else to earn forgiveness, we must but accept the fact that Jesus is the substitution for all we cannot do and really believe that.
All that is required of us is to admit we cannot work enough, pray enough, be good enough or anything else to earn forgiveness, we must but accept the fact that Jesus is the substitution for all we cannot do and really believe that and be thankful for that.
Serving God is equally simple, there are two pieces of scripture in the Bible that says it all. They are immediately below:
 One of the scribes came and heard them arguing, and recognizing that He had answered them well, asked Him, "What commandment is the foremost of all?"  Jesus answered, "The foremost is, 'Hear, O Israel! The Lord our God is one Lord;  and you shall love the Lord your God with all your heart, and with all your soul, and with all your mind, and with all your strength.'  The second is this, 'You shall love your neighbor as yourself.' There is no other commandment greater than these." Mark 12: 28-31
And Matthew said the same:
"Teacher, which is the great commandment in the Law?"  And He said to him, "'You shall love the Lord your God with all your heart, and with all your soul, and with all your mind.'  This is the great and foremost commandment.  The second is like it, 'You shall love your neighbor as yourself.'  On these two commandments depend the whole Law and the Prophets." Matthew 22:36-40