Who are we really offending?

I have just started to read a book entitled, "When Sinners Say, 'I Do' ", by Dave Harvey, and it is certainly not your average marriage "self-help" book. As you might have guessed from the title, the focus of the book is not on "Three key principles of communication" or "Seven ways to divorce-proof your marriage", but understanding the heart of the whole matter of why marriage (and life!) is not and will never be perfect - because WE are the problem (we're sinners!).
Once we have this concept understood, it is easy to see why even the best marriages have conflict, hurts, and less-than-perfect stories to tell. While there are many aspects of sin that the author talks about as he lays the groundwork for recognizing we are sinners, one of the points he made that stuck out to me is on the issue of sinning against others. Harvey makes the claim (to which I agree) that while we sin against other people, such as our spouse, children, friends and other family, our sin is "most strongly, and therefore primarily, against God! ...Every sin, however small or great its apparent impact on people, violates the purity of the perfectly just and holy God. Sin is always aimed first and foremost against God (Deut. 9:16, 1 Sam. 15:24, Ps. 51:4)."
This is truly something great to understand, for when we realize that our sin does not just affect ourselves and others, but each sin is also a direct offense to the author and sustainer of the universe, we realize that an empty, "I'm sorry" does not satisfy God's call to repentance. Being human, as we are, we like to maximize pleasure and avoid pain - but this is not the call of a Christian. We must realize the true gravity of our sin, seen by God as a rebellion against His perfect ways, and then confess it before Him, repent of our continued sinfulness, realize God's mercy and grace in His forgiveness of our sin, and then turn from it into His way. When we realize who our sin is really offending, we get to the heart of the matter, and can then practice grace and forgiveness toward those who offend us (reminescent of the Lord's prayer: "forgive us our debts, as we forgive our debtors").
Taste and see the grace, mercy, and peace that comes from knowing God has forgiven His children even when we do not acknowledge we have sinned against Him! "For it is by grace I am saved, through faith, and this not of myself - it is the gift of God."