This is a modern day scripture from our Doctrine and Covenants, but I think everyone will agree that it is true: "For I the Lord cannot look upon sin with the least degree of allowance;"(Doctrine and Covenants 1:31). First of all, we must answer the question, "What is sin?". Sin is defined in the dictionary as "transgression of divine law". "Law" refers to the commandments that God has given us. If God accepts sin, then he ceases to be God. Part of what makes him God is that he is the opposite of evil. There are no gray areas between sin and righteousness. Either we are obeying the commandment, or we aren't. And so God cannot accept even a "little sin". Can even a little sin be accepted in heaven? If it were, it wouldn't be heaven, would it?
Most Christians believe that Christ paid for our sins. But we differ in our beliefs about how that works for us. Some believe that all we must do to be "saved", is to confess Jesus as our Savior. We believe that having faith in him is essential to salvation, but in order for that faith to work in our lives, we must also have repentance. When we repent, and exercise faith in the atonement of Jesus Christ, our sins are forgiven. If God does not require us to repent, then he is allowing sin. Let me use an example to illustrate this point.
Recently our school district met with the High school administrators and announced that teachers would no longer be allowed to flunk any student. I think the concept behind this is that if we want "no child left behind", then we can't flunk them. But what will result from this mandate is that students will soon learn that they need not do any work in order to graduate. They just show up, and their graduation is assured. Can you see how detrimental this is to the development of the students? If the school board really cared about the progression of the students, they would repeal this requirement, and allow there to be a consequence for lack of effort on the part of the student. So too, if God does not have a consequence for sin, people will have no reason to live righteously, nor to improve themselves. If "showing up", or "confessing Jesus" is enough for salvation, why even try to do what is right? There are those who will argue that if you love Jesus, you will obey the commandments naturally. But that is not the nature of man. "For all have sinned, and of the glory of God;" (Romans 3:23). If God is God, then he will want us to be the best we can be. That can only come about through repentance.
The Book of Mormon teaches, "For the natural man is an enemy to God, and has been from the fall of Adam, and will be, forever and ever, unless he yields to the enticings of the Holy Spirit, and putteth off the natural man and becometh a saint through the atonement of Christ the Lord, and becometh as a child, submissive, meek, humble, patient, full of love, willing to submit to all things which the Lord seeth fit to inflict upon him, even as a child doth submit to his father." Mosiah 3:19
The Book of Mormon also teaches "For it must needs be, that there is an opposition in all things. " 2 Nephi 2:11. If there is happiness in the world, there is also sadness. If there is comfort in the world, there is also pain. If there is righteousness in the world, there is also sin. We also read in the Book of Mormon: "And if ye shall say there is no law, ye shall also say there is no sin. If ye shall say there is no sin, ye shall also say there is no righteousness. And if there be no righteousness there be no happiness. And if there be no righteousness nor happiness there be no punishment nor misery. And if these things are not there is no God. And if there is no God we are not, neither the earth; for there could have been no creation of things, neither to act nor to be acted upon; wherefore, all things must have vanished away." 2 Nephi 2:13.
Sin does exist in the world, but the sacrifice of Jesus Christ can atone for sins that we commit, upon condition of our repentance. For him to remain perfect, Christ saves us "from" our sins, not "in" our sin. Without repentance, we do not change. Without repentance, the same person that we have become in this life, no matter how evil, or sinful, will be the same person that will be resurrected. I submit to you that if that same sinful person is allowed in to heaven, then it will not be heaven. Repentance then, can be thought of as a type of spiritual resurrection. When we repent, we put off the natural man in us, and strive to be more like Christ. Without repentance, how can this occur?
I am thankful that God is perfect, and without sin, and that heaven is a place where sin is not allowed. I am thankful for the Savior who atoned for our sins so that we can repent and be forgiven. We, of ourselves, could never make up for the wrongs that we do. But Jesus' sacrifice meets the demands of justice so that we can be forgiven. This is the "good news" of the gospel of Jesus Christ!