Understanding the nature of sin is crucial in these last days; understanding what really happened at creation will give you strength above any and all that can bring an assault, even death.  And if death be conquered, all else that brings an offense must be seen for what it is.
 
Knowing that God is righteously infinite in all that He is speaks a simple truth that will aid in our journey into sin.  To have no beginning or end is only possible for one being, who is God.  To bring into existence any other being automatically qualifies that being as having a moment of birth, if you will.  Being outside of infinity in this manner is enough to qualify any created being as lesser-than-God.  This does not necessarily mean that any being that God creates is sinful.  Angels in heaven, for example, are not infinite but neither are they sinful. 
 
It is hard for us to imagine the realm of heaven.  Its glories are expressed in the Psalms as being a place where an abundance joy is found in the presence of God and at His right hand will be pleasures forevermore.  It is a place where sin will not be found but not necessarily for the reasons that you have been told.
 
As some think of Him, God is not the author of a cruel cosmic game wherein His boredom led Him to create creatures that experience pain, put them in a painful environment, and then create constant glimpses of hope only to dash them against uncontrollable forces.
 
God began by creating a place void of Himself and formed energy that would be the substance of all that He makes.  As He made the earth, He made it in such a way that it would tell something about Himself.  The being of God is good and perfect and He has declared Himself to be perfect love, which is to say that His motives and actions are never sinful.  Sinfulness is the opposite of righteousness. So it was declared by God that He would make the environment of this new world in such a way that the creatures that were to survive in this environment would have to do so in the opposite way in which God acted.  Creation's actions were to be a mirrored image of God's actions.   
 
In each kind of living being, with the exception of an oddity or two, He made them in opposite pairs and designed the inner workings of their elaborate machine to transmit half of its design to its opposite, making a new machine that had the traits of both parent machines.  This ability to move within its own environment and perpetuate itself was called life.  Life was made to be desired by each creature so that it would make efforts to continue its life.
 
The desire for life in the creature was first and foremost a concern for its own life and it was lived out in each as a fear of death.  Death was made to be the great enemy of each living creature and certain design qualities were added to each machine so that it could interact with its environment.  To each one was given the ability to sense its surroundings.  If a threat to the life of the creature was to be perceived than certain chemicals would flood the internal system of this machine and cause it to experience gripping fears of death, followed by the sudden ability to flee or fight for itself in fear.
 
These machines were also made contrary to God in that their survival behaviors would cause them to act contrarily to the nature of God.  To provide energy for itself, many would kill another living being so as to provide itself with energy.  Other creatures that were made stronger had the ability to steal its sustenance from another creature that had performed the work necessary to obtain it.  And seeing that God is faithful in all of His relationships he made these creatures in opposites that they might have a relationship but the one that was to deposit half of his features to the other would unfaithfully do so with any willing counterpart that he could find.  This unfaithfulness in the spreader-of-his-seed, by the way, is precisely what the Apostle Paul spoke of when he said that nature teaches us that long hair shames the man. 
 
Though much more can be said of God's creation, we now have the few necessary components of God's creation to come face to face with ourselves and clearly see the nature of sin.
 
The body that a man or a woman has sustains itself, protects itself, and perpetuates itself in the same way that every creature does.  It has eyes in order to see that which it needs; it has sensations within itself that tells it what it needs, which is called the flesh in the Word of God; it has a pride of life, which is also a fear of death; and it has strong natural desires with which it seeks out a mate to become one flesh with.  The human shell survives in an opposite fashion to the nature of God.
 
These qualities were in the first to be created, Adam and Eve,  It is expressed about Eve in the Hebrew text that she had an idolatrous desire for the tree that would make one wise.  She ate first.  But we also see the fear of death at work in Adam because he was afraid to eat from the tree because God had told him that he would die if he did.  When the woman ate and he saw that she did not die, the pride of life in Adam, which kept him from eating from the tree at first, reared its head in the form of pride to gain a stronger and better life.
 
These idolatries in her, and the pride in him, were a natural part of their worldly forming.  It is his pride that causes the male of a species to flash his grand feathers, or rev his fast car.  Her natural idolatries cause her to desire the one who flashed their feathers in the grandest fashion.  It is how the male and the female come together for the purpose of perpetuating their species.  God added great pleasure to the act of procreation to counteract a creature's natural fear of death but also to encourage a repetition in their mating. 
 
Eating from the tree was a punishable offense to Adam for one reason.  God had made a rule against eating from the tree and had told Adam that his penalty would be death if he did.  Prior to Adam's breaking of the commandment, his environment was no threat at all to him and the natural desires that God had put into his creature did not act in the way of all the other creatures.  Each day Adam had walked personally with God and everything was paradise, even his relationship with his wife, Eve.
 
It is important here to see what actually happened in the Garden of Eden that day.  It says that even before the breaking of the commandment that Eve expressed an idolatrous desire towards the potential found in the fruit.  It would make one to be wise like God.  She had this in her, in her flesh that is, because it is an idolatrous desire in nature that causes the female of a species to become enticed by the displays of the male species as he pridefully flaunts his display of beauty before her.  In nature, the female is always seen as the weaker vessel, as even Paul spoke in the same manner about the wife of a husband.  She too is the weaker vessel.  It is the man in nature that has the longer more attractive coverings, the long hair in nature alluded to earlier.  How can this be?
 
It is because the human spirit that was put into each man and woman is the real person.  The body, which is referred to as a tent in Scripture, is just that, a tent which houses a real living person.  It is not the body that makes us what we are.  The mysterious truth that has been hidden from the eyes is that our bodies are the nature of sin and the acts that it carries out in this realm are meant for the perpetuation of the body.  As mentioned above, God created this natural realm to have creatures in it that survived by acting in an opposite way that God would.  
 
When Adam sinned his daily fellowship with God ended.  And the Scriptures say that his eyes were opened.  Which eyes?  The eyes that we see with.  Adam's physical eyes were opened to the pains of survival in this world of opposites and one of the first prophecies in the Bible became a reality.  The man and the woman became one flesh.  This is to say that they were no longer able to fellowship according to their true spiritual identity and were cast into a dog-eat-dog world where they would exist like all of the other animals and their respective curses would haunt them all of their days.  The implications of this are simple.  Gaining understanding of this is blocked by Satan himself.
 
The body itself is the nature of sin.  It was created to survive in the same way that all other animals survive.  Some hunt vegetables; some work hard to gain a meal; some steal; all fear death.  Not only do the animals of this realm have the natural ability to sense and react to potential and real death threats, the same chemicals that flood the body of a scared rabbit flow through the veins of men and women.  The same kind of eyes that belong to a lion and pierce its next meal are in us.  The same physical needs that causes animals to seek out sustenance for its flesh are in us.  The same fear of death, which is the pride of life, haunts each living man and woman that God has created. 
 
This is precisely what the Apostle John meant in 1 John 2:15-17 when he said, "Do not love the world or the things in the world.  If anyone loves the world, the love of the Father is not in him.  For all that is in the world - the lust of the flesh, the lust of the eyes, and the pride of life - is not of the Father but is of the world.  And the world is passing away, and the lust of it; but he who does the will of God abides forever."
 
Pay close attention to exactly what John has said.  These behaviors are not of the Father.  They are of the world.  This world was made to express the opposite of God's character and each creature survives in ways that are called sin.  This is why Paul has told us two things about mankind that are a display of this truth.
 
The first tells us that even though sin was in the world it was not counted as sin because there were no laws yet given to say that it was sin.  God's creation of persons who were designed to live in this certain kind of realm and act sinfully to survive is how things must be.  Any creation of God will be lesser than Himself.  But Paul also told us that it was the giving of the law that condemned the behavior of all creatures who were made in the image of God.
 
Because death had come on all men and women, they were forced to live their existence like the animals of the field.  Because Paul has told us that nature was created in a futile way, being no moral decisions behind their displays of sin, we learn that because we were created as moral, thinking, and reasoning creatures that when God gives a commandment against our actions we are condemned by actions and decisions that are a result of our natural forming.  Sin is not an evil twisting of the spirit of a man that came after he had disobeyed the first commandment given to him.  It is that his spiritual eyes were closed and he was forced to live like the natural part of himself that was formed only to survive in this realm.  Mankind was not condemned for living out their natural ways until the law was given (Romans 5:13).
 
The qualities and displays of sin were in the first man and woman before the original breaking of the commandment.  It is because there were no laws against their actions that it was not counted as sin, though it was said that sin was in the world.  It was the giving of commandments that made us guilty as Paul has also said that he would not have known that he was an idolater unless the commandment had told him "You shall not covet."
 
All of this together can lead to only one conclusion.  Paul's reference to a body of sin means that this body and all that it does to survive in this realm is sin.  When Paul said of Jesus that he "was made" sin meant that He took on the form of a creature that was designed to live in this realm.  He took on the same kind of body that we have.  It became hungry and He ate; it became thirsty and He drank; it became tired and He rested.  This makes His temptations as real as ours are.  This means that He fully does understand from our perspective and as a result He is a faithful High Priest in our behalf, a true and faithful mediator.  
 
Be careful not to think of Jesus as a sinner.  He was not.  Though he took on the form of sin it can be said of Him that He never one time acted like an animal. 
 
Sin will not be found in Heaven.  You will have a different kind of body (1 Corinthians 15:40).