There is a difference between forgivable sins, pardonable sins, and unpardonable sin.
Forgivable sins consist of past sins that you have committed where you have knowingly rebelled against the best you understood. To this point in this book, we have confined our definition of sin to these actions.
Another definition of sin is anything less than the perfection of God. This definition includes our former definition, but proceeds beyond the limits of your understanding to include everything that deviates from God’s perfection.
There is a difference between sins committed knowingly and sins committed ignorantly. Conscientious sins must be forsaken in order to be forgiven. Sins committed in ignorance can be pardoned, meaning they do not require change in order to be forgiven. The vast difference between our best idea about God and how he actually is comprises the space of “pardonable” sin.
The sacrifice of Jesus Christ makes it possible to become like he is through living the best we know and remaining reconciled to each additional increment of knowledge he gives us, line upon line. It gives us a way to be saved through living the best we know, rather than the best there is.
When we obey all that we presently know about God, the Lord forgives us of our previous sins committed knowingly, but he does not give us permission to commit future sins with knowledge. If we commit additional sin knowingly, we separate ourselves from his forgiveness and from any progress, as we will have cut ourselves off from the Holy Ghost:
8 ...men of corrupt minds, reprobate concerning the faith. 9 ...shall proceed no further.... (2 Timothy 3)
Our repentance qualifies us for the Lord’s forgiveness of not only all our known sins, but also all sins of ignorance: past, present, and future.
When Jesus said to be perfect like he is and like the Father is, he did not say “be as perfect as you understand us to be.” The commandment is for all of us to be exactly as they are. However, because we cannot become like them beyond the limit of our present knowledge, the sacrifice of Jesus Christ provides a pathway where we can become like they are, line upon line, as the Lord teaches us more about himself and the Father (see the previous chapter).
The unpardonable sin is unpardonable because it violates the condition that makes possible the forgiveness of both past sins of which we know and past, present, and future sins of which we don’t know:
But whoso breaketh this covenant after he hath received it, and altogether turneth therefrom, shall not have forgiveness of sins in this world nor in the world to come. (D&C 84:41)
When you commit the unpardonable sin, you are in open rebellion against God because you are violating his will as far as you understand it by doing differently than you believe he would in your situation. This makes it impossible for him to forgive you, because it violates the conditions he has declared for that forgiveness to occur.
There is a difference between forgivable sins (past conscientious sins), pardonable sins (past, present, and future sins of ignorance) and unpardonable sin (knowingly rebelling against God).