It begins with the definition of God's Law. From one perspective, it's totally unyielding, a thing either obeyed or violated. However, the plain fact that forgiveness from God is possible, means that an additional dimension exists. Some people confuse forgiveness to mean that God will excuse sin, which is not a valid concept to me. Others suggest that God forgives sin, but there are different levels, so that someone forgiven is still not as good are pleasing to God as one who does not sin in the first place. The account of Jacob, however, makes an early case that God's forgiveness is totally perfect, and so a sin is made as if it never happened, and will not be remembered in any form.
Assuming that interpretation is correct, then the Law is something more mysterious; inflexible, yet there is a way to obey it beyond Man's understanding, and the key is the Will of God.
In writing about sin, I think the first point to make is that sin is about Man, not God. What I mean there, is that God is holy and perfect, regardless of whatever a person does; to claim otherwise would give sin a power over God, which is not at all true. So, even if every man, woman and child on the earth were to live a wholly sinless life, God would not become more perfect or holy, as He is already the Absolute. Also, even if every single man, woman and child were to become unutterably evil and vile, it would not diminish the perfection or holiness of God at all. Therefore, the action of sin is Man’s alone, and the effect of sin is Man’s alone. Whether we mean sin to be “evil”, to “miss the mark”, or anything in between, it is Man’s condition which is concerned by sin, and so when God speaks to us concerning sin, it is our condition He addresses.
Now then, when a man becomes aware of his sin, he may react in a number of ways. He may deny his sin, which is the common response, but that only delays coming to understand his condition. When he finally understands his condition (meaning he finally stops denying he has sinned, he stops trying to blame his wrong on someone or something other than himself), he must either repent of his sin, or else he holds on to his sin. If he holds on to his sin, he accepts the full measure of the sin’s effect. If he repents, then things get interesting.
First, there is the sin which is forgiven, but some sort of consequence still happens. It’s kind of like when the Fire Department comes and puts out the fire, but you still have damage from the fire. When sin happens, there are consequences, not always obvious, but they are there and must be dealt with.
Yet, it also happens that there are sins which are made as though they never happened, in G-d’s eyes. God does not keep records on forgiven sins, nor hold a man accountable for any sin in the past, which God has forgiven. Many people do not like this point, since it appears to some to give support to the notion that a man might sin as much as badly as he pleases, provided he says he’s sorry for it later. My counter to that notion, is to note that God is not fooled by fake contrition, nor is He unaware of what a man means to do in the future. So, even if a man believes he is truly sorry, if he means to go sin again later in the same way, or if his heart still holds to that sin in spirit, the LORD knows this, and there is no forgiveness until and unless that contrition is made real.
To the third point, I remember an old story, about a wise master whose disciples hoped to learn from him. The master said he would grant full knowledge, if they could produce the ‘right stone’. So, the disciples went out and found stones; great stones, small stones, smooth stones, rough stones, of every kind and they brought them, one by one, to the master. But the master only said ‘No, wrong stone’ every time.
There is no moral to that story, because it is not that kind of story. But the story reminds me that God is not like that cruel master, who has secret knowledge he will not share. Rather, the LORD makes His gifts freely available to us all. We just have to accept them. Reading through what I know as the Old Testament, I see prophets, visions granted to men and kings, angelic visits, all to give people the instruction and direction they need. Yet throughout History, people continue to fail and fall. This is not a thing which pleases God, as is evident from Scripture.
Presuming God is in position and of a mind to help us find the way He has set ready for us, it follows to me that He would do so in the most effective way possible. Yet it also follows, that God must remain God, holy and completely perfect. How then to reach sinful Man, when Man would be destroyed by God’s presence? I find it likely that God would send Himself, once, as a perfect example, and this explains the identity and purpose of Messiah.
Jews do not, I know, accept this, but Christians very much do, that the Messiah was God in person coming to be a human, and it serves the need well. Man cannot say that God does not know what it is to be unjustly hurt, as this happened to Jesus all His life. Man cannot say the perfect life is impossible, because Jesus lived it. And because Jesus died on the cross for us, no man or power can claim the debt is unpaid.
Obviously, the first question that comes up from this explanation, is just how God can walk among us, being perfect. What happened is, knowing beforehand all that Men would do, God made Himself in three persons but of the same essence and being. It is difficult to explain the Trinity, but that should not be surprising, given the task of explaining a Divine quality necessary to allow perfect reign in Heaven, yet complete contact with humans here on Earth. As for the Holy Spirit, that one shows up many times throughout the Bible, especially in the words of David and in the Scripture concerning Moses, so God was able to be in both Heaven and Earth simultaneously from the beginning.
This also explains the requirement that Jesus should be sinless. Not because we humans must be perfect in order to be forgiven by the LORD, but because Jesus is the template for perfection, proof that it can be done. You see, when we sin, we all sin against God. Remember Psalms 51:4, where David confesses “against You, You only, have I sinned”? What a strange thing to say! Because of David’s sin, Uriah was dead, Bathsheba disgraced, and his infant son killed. Yet David says he only sinned against God (and Psalm 51 was written specifically because of Nathan’s charge against David). What David meant, was that whatever we do, as bad as it is to any person on Earth, it is God who has the full right, and to whom we therefore owe contrition and penitence. It would create a conundrum, were God to sin against God! More, Davis defines “blameless” for us in Psalms 19:13, as “innocent of great transgression”. Blameless is not perfect, but God is perfect. Consider the 119th Psalm, especially verses 97-104 and 125. Why meditate upon the Law, or work to achieve insight and discernment, if the Law is a simple matter of obeying a technicality? David makes clear, that the Law is a thing much deeper than a superficial code of conduct, and Jesus reinforced that by His actions and words in practice.
Jesus did not sin, and no man who follows His way will sin. The problem, of course, is that as willing as we are to do the right thing, we fail because we are weak.