Not about sin? Sorry, Doc, you'll have to take that up with the Lord:
Mt:5:22: "But I say to you, that whosoever is angry with his brother, shall be in danger of the judgment. And whosoever shall say to his brother, Raca, shall be in danger of the council. And whosoever shall say, Thou fool, shall be in danger of hell fire."
Mt:18:9: "And if thy eye scandalize thee, pluck it out, and cast it from thee. It is better for thee having one eye to enter into life, than having two eyes to be cast into hell fire .
Mk: 9:42: "And whosoever shall scandalize one of these little ones that believe in me: it were better for him that a millstone were hanged about his neck and he were cast into the sea. 43 And if thy hand scandalize thee, cut it off: it is better for thee to enter into life, maimed, than having two hands to go into hell, into unquenchable fire: 44 Where their worm dieth not, and the fire is not extinguished. 45 And if thy foot scandalize thee, cut it off: it is better for thee to enter lame into life everlasting than having two feet to be cast into the hell of unquenchable fire: 46 Where their worm dieth not, and the fire is not extinguished. 47And if thy eye scandalize thee, pluck it out: it is better for thee with one eye to enter into the kingdom of God than having two eyes to be cast into the hell of fire: 48Where their worm dieth not, and the fire is not extinguished. 49For every one shall be salted with fire: and every victim shall be salted with salt."
Mt:10:28:"And fear ye not them that kill the body, and are not able to kill the soul: but rather fear him that can destroy both soul and body in hell.
Mt:11:23: "And thou Capharnaum, shalt thou be exalted up to heaven? thou shalt go down even unto hell. For if in Sodom had been wrought the miracles that have been wrought in thee, perhaps it had remained unto this day."
Lk:20:47: "Who devour the houses of widows, feigning long prayer. These shall receive greater damnation."
What is a Mortal Sin?
In order for a sin to be mortal, it must meet three conditions:
Mortal sin is a sin of grave matter
Mortal sin is committed with full knowledge of the sinner
Mortal sin is committed with deliberate consent of the sinner
In the Bible, St. Paul gives us a list of grave sins. He states that anyone who commits these sins shall not enter the kingdom of God. “Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God” (Galatians 5:19-20). Paul also tells the Corinthians, “know you no that the unjust shall not possess the kingdom of God? Do not err: neither fornicators, nor idolaters, nor adulterers, Nor the effeminate, nor liers with mankind, nor thieves, nor covetous, nor drunkards nor railers, nor extortioners shall possess the kingdom of God” (1 Corinthians 6:9-10). These sins constitute grave matter, and if they are committed willingly and with full consent, constitute mortal sin.
The Church also tells us that the sins of anger, blasphemy, envy, hatred, malice, murder, neglect of Sunday obligation, sins against faith (incredulity against God or heresy), sins against hope (obstinate despair in the hope for salvation and/or presumption that oneself can live without God or be saved by one’s own power) and sins against love (indifference towards charity, ingratitude, and/or hatred of God) also constitute grave matter. This list of grave sins, is based on Jesus Christ’s interpretation of the gravity of the Ten Commandments. Grave sins can be classed as sins against God, neighbor and self, and can further be divided into carnal and spiritual sins (CCC 1853).
Four other sins are considered grave also. These sins not only offend God, but men as well. Thus these four sins are called “the sins that cry to heaven for vengeance” and are likewise mortal sins. These grave sins are:
The voluntary murder (Genesis 4:10)
The sin of impurity against nature –Sodomy and homosexual relations (Genesis 18:20)
Taking advantage of the poor (Exodus 2:23)
Defrauding the workingman of his wages (James 5:4)
Finally, the capital sins are also considered grave matter. These sins are vices and are defined as contrary to the Christian virtues of holiness. They are pride, avarice, envy, wrath, lust, gluttony, and sloth (acedia).