Many of us, throughout our growing up, can give an answer to what the greatest sin is. And, for sure, I know that many of us have even heard of the movie entitled SEVEN, back in 1995, starring Brad Pitt and Morgan Freeman, where the plot outline speaks about two cops, one new and one about to retire, after a serial killer using the seven deadly sins as his MO.
The Sins, which are listed in order of increasing severity, as Pope Gregory the Great, from the 6th century, calls the seven deadly sins which are as follows:
Lust (fornication, perversion) Depraved thought, unwholesome morality, desire for excitement, or need to be accepted or recognized by others. Obsessive, unlawful, or unnatural sexual desire, such as desiring sex with a person outside marriage or engaging in unnatural sexual appetites (like bestiality.) Rape, adultery and sodomy are considered to be extreme lust and are said to be mortal sins. Dante’s criterion was “excessive love of others,” thereby detracting from the love due to God. Lust prevents clarity of thought and rational behavior. Lust is symbolized by the snake in most Christian religions and the color blue, although it can also be associated with the cow. The punishment in hell for lust is being smothered in brimstone and fire.
Gluttony (waste, overindulgence) Thoughtless waste of everything, overindulgence, misplaced sensuality, uncleanliness, and maliciously depriving others. Marked by refusal to share and unreasonable consumption of more than is necessary, especially in the case of food or water. Destruction, especially for sport (like trophy hunting.) Substance abuse or binge drinking. Dante explains it as “excessive love of pleasure”. Associated with pigs and the colour orange. The punishment in hell for gluttony is being force-fed rats, toads, and snakes.
Greed (treachery, covetousness) A strong desire to gain, especially in money or power. Disloyalty, deliberate betrayal, or treason, especially for personal gain or when compensated. scavenging and hoarding of materials or objects. Theft and robbery, especially by violence, trickery, or, worst of all, manipulation of authority. Simony is the evolution of avarice because it fills you with the urge to make money by selling things within the confines of the church. This sin is abhorred by the Catholic Church and is seen as a sin of malice; Dante included this sin in the first poem of the Divine Comedy (the Inferno). Simony can be viewed as betrayal. Thomas Aquinas on greed: “it is a sin against God, just as all mortal sins, in as much as man condemns things eternal for the sake of temporal things.” Greed is often seen as the most childish of the 3 exaggerated adulthood sins, because it often focuses on short-term gains. An extreme form of gluttony. Greed is represented by the frog and the color yellow.  The punishment in hell for greed is being submerged in the finest boiling oils. It can also mean to endour or to induce some topics.
Sloth (apathy, indifference, laziness) Apathy, idleness, and wastefulness of time. Laziness is particularly condemned because others must work harder to make up for it. Cowardice or irresponsibility. Abandonment, especially of God. Sloth is a little like a state of equilibrium: one does not produce much, one does not consume much. However, sloth, unlike homeostasis, leads only to despair. Dante wrote that sloth is the “failure to love God with all one’s heart, all one’s mind and all one’s soul”. Associated with goats and the color light blue. The punishment in hell for sloth is being thrown into a pit of snakes.
Wrath (anger, hatred, prejudice, discrimination) Inappropriate [unrighteous] feelings of hatred and anger. Denial of the truth to others or self. Impatience with the law, or seeking revenge outside of justice. Unnecessary vigilanteism. Wishing to do evil or harm to others. Disliking others for no good reason, such as their race or religion, leading to discrimination. Self-righteousness. Wrath is the root of murder, assault, discrimination, and, ultimately, genocide. (See Crimes against humanity.) Dante described wrath as “love of justice perverted to revenge and spite”. The childish of the two prolonged adolescence sins, being hard to safeguard against especially in the case of people in teens and 20s. Wrath is considered childish because hatred is often born out of misunderstanding, or the inability to forgive. Wrath is symbolized by the bear and the color red. The punishment in hell for wrath is being dismembered (probably over and over again, like the eagle that repeatedly eats Prometheus’s liver every day in Greek mythology.)
Envy (jealousy, malice) Grieving spite and resentment of material objects, accomplishments, or character traits of others, or wishing others to fail or come to harm. Envy is the root of theft and self-loathing. Dante defined this as “love of one’s own good perverted to a desire to deprive other men of theirs.” An extreme form of greed/avarice. It is associated with the dog and the color green. The adolescent of the 3 exaggerated adulthood sins. The punishment in hell for envy is being placed in freezing water.
Pride (vanity, narcissism) Pride is known as the father of all sins. Pride is a desire to be more important or attractive to others, failing to give credit due to others, or excessive love of self (especially holding self out of proper position toward God). Dante’s definition was “love of self perverted to hatred and contempt for one’s neighbor”. In Jacob Bidermann’s medieval miracle play, Cenodoxus, superbia is the deadliest of all the sins and leads directly to the damnation of the famed Doctor of Paris, Cenodoxus. Pride was what sparked the fall of Lucifer from Heaven, and his subsequent transformation into Satan. Vanity and Narcissism are good examples of these sins and they often lead to the destruction of the sinner, for instance by the wanton squandering.
We could even go on and name many of others if we would put our thoughts to it but each persons perspective would be different because of the way they have both been raised and even influenced by their family members, church and friends.
Becoming influenced, by someone or something, when defined it means:
The exercise of moral control over the actions of another
Even, Psychologist Adam Cash says, social and cultural factors  can affect ones behavior because when it comes to the cognitive factor, which focuses on the metal processing of information, including the specific functions of reasoning, problem solving, and memory, it shows us that the mental plans and thoughts guide and cause behavior. And it is my personal belief that what guides and causes our behaviour, is basically those, things or people, that influences us.
We can become influenced by many things and even in many ways, but what matters the most is the truth.
Romans 10:17 (NKJV) So then faith comes by hearing, and hearing by the word of God.
2nd Timothy 2:15 (NKJV) Be diligent to present yourself approved to God, a worker who does not need to be ashamed, rightly dividing the word of truth.
What 2nd Timothy 2:15 is asking of us is to study and to rightfully divide the word of truth which basically is saying to let scripture interpret scriptures. And, when we let scripture becomes its own interpreter
So, if we let scripture becomes its own interpreter, what then would be the greatest sin? It would seem to be that the greatest sin, according to scriptures would have to be unbelief for as John 16 proclaims
John 16:8-9 (NKJV) And when He has come, He will convict the world of sin, and of righteousness, and of judgment: 9 of sin, because they do not believe in Me;
So, as we can tell by the scripture alone it would then be declared that the worse sin would be none others then unbelief wouldnt you agree?
1st Cor. 1:18, 25 (NKJV) For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God. 25 Because the foolishness of God is wiser than men, and the weakness of God is stronger than men.
Just by reading Numbers 14, we are able to read that Joshua and Jephunneb, who spied out the land, were encouraging the people to trust in God for if God said He would do something then He would do it but the people, who Joshua and Jephunneb spoke to, felt betrayed by God and felt better off back in bondage in Egypt for it was their they have felt more at peace since their whole life was spent back there. But, when it comes to true freedom, sort of like those in Iran who are no longer under the control of Sadam, they cry out wishing to have the life of bondage instead of freedom which we can see the doubt within the people because they are leaning upon their own understandings which Proverbs 3:5-6 asks of us not to do:
Proverbs 3:4-5 (NKJV) Trust in the Lord with all your heart, And lean not on your own understanding; 6 In all your ways acknowledge Him, And He shall direct your paths.
Although unbelief would seem to be the greatest sin, which all humanity has fallen into at birth, because of the adamic fall:
Romans 5:12 (NKJV) just as through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned.
I, myself, in my own personal conviction would have to say that there is no such thing as one sin being greater then the other because when we read the letters of Christ and even Paul they proclaim:
Matt. 5:27-28 (NKJV) You have heard that it was said to those of old, You shall not commit adultery. 28 But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart.
Romans 7:7-12 (NKJV) What shall we say then? Is the law sin? Certainly not! On the contrary, I would not have known sin except through the law. For I would not have known covetousness unless the law had said, You shall not covet. 8 But sin, taking opportunity by the commandment, produced in me all manner of evil desire. For apart from the law sin was dead. 9 I was alive once without the law, but when the commandment came, sin revived and I died. 10 And the commandment, which was to bring life, I found to bring death. 11 For sin, taking occasion by the commandment, deceived me, and by it killed me. 12 Therefore the law is holy, and the commandment holy and just and good.
Rom 3:23 (NKJV) for all have sinned and fall short of the glory of God,
and by reading what they are proclaiming we can then see that we have all come short of the glory of God; although we have come short we do have hope because as (Gal. 3:24) and (Rom 6:23) proclaims:
Galatians 3:24 (NKJV) Therefore the law was our tutor to bring us to Christ, that we might be justified by faith.
Rom 6:23 (NKJV) For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
we can then come to the conclusion that for those of us whom the Holy Spirit draws we have hope in Christ and today that hope can be a reality for you all.