I sin. I act in ways that hurt others, I sometimes say mean and hurtful things. When I speak and act this way I am sinning against those people…right??
David committed adultery with Bathsheba, to cover it up he ordered Uriah, her husband killed. He married Bathsheba and thought all is well. David didn’t acknowledge the truth of his actions until he is confronted by the prophet, Nathan. Psalm 51 is David’s song of confession and plea for forgiveness. It begins below…
1 Be gracious to me, O God, according to Your lovingkindness;
According to the greatness of Your compassion blot out my transgressions.
2 Wash me thoroughly from my iniquity
And cleanse me from my sin.
3 For I know my transgressions,
And my sin is ever before me.
4 Against You, You only, I have sinned
And done what is evil in Your sight,
So that You are justified when You speak
And blameless when You judge.
WAIT…how can David say he only sinned against God?
Certainly David sinned against Bathsheba, didn’t he? Then there is the matter of her husband, and David likely sinned against many other people during the months following these events, before being confronted by Nathan, the prophet. When people hurt me, they sin against me. Don’t they? When I hurt others I sin against them. Right?
What does David mean he ONLY has sinned against God?
To understand the point David is making, we need to start with a correct understanding 
of the word “sin”. The Hebrew word transliterated sinned is Chataʾ, which means “to miss the mark,”. The word literally refers to a person shooting a bow and arrow and missing the target with the arrow. When it is used to describe sin, it means that the person has missed the mark that God has established for the person’s life.
When we fail to meet God’s ideal, we sin.
And our sin is only against God, because He is the one who set the standard. Our hate, anger, hostility, etc…brings pain to ourselves and the people we direct it toward. But ultimately our sin is against God. We like David must confess our sins and acknoweldge the evil we have done in God’s sight. Then repent, and ask for His mercy and forgiveness.
As for me, I said, “O Lord, be gracious to me;
Heal my soul, for I have sinned against You.” Psalm 41:4
And like the prodigal son, we need to acknowledge our sin to the people we have hurt and ask for their forgiveness.
I will get up and go to my father, and will say to him, “Father, I have sinned against heaven, and in your sight; Luke15:21
The eyes of the Lord are toward the righteous
And His ears are open to their cry.
Psalm 34:15
Heartland Precepts 