These words, attributed to King David in the fifty-first Psalm, have been explained away by numerous Bible commentators down through the ages. After all, the psalm was ostensibly written on the occasion of his repentance for his sinful behavior in the matter of Bathsheba and Uriah. And, as Wayne Jackson noted in his article "Did David Sin against God Only?" for Christian Courier, it is obvious that David "had sinned against the woman with whom he committed this act of vileness. He had sinned against Uriah, Bathsheba’s husband. He had sinned against his family. He had sinned against his own body (cf. 1 Corinthians 6:18). David had sinned against his men, who had a right to expect fidelity from their leader; similarly, in an even broader sense, he has betrayed the nation he led."
Hence, the need to explain David's apparent obliviousness to the fact that he had indeed sinned against others. That is why many of these commentators have insisted that David's words on this occasion are not to be understood literally or absolutely. In other words, he could not have really meant what is clearly suggested by him in this verse - that God is the ONLY one whom he has sinned against. For many of them, David is engaging in hyperbole. For them, he is so devoted to God that his sins against others pale in comparison to his sins against God.
But what if David really meant what he is reported to have written here? We are told that David loved God's law and thought about it continuously. Is it possible that David came to the same conclusions about the implications of God's law which are attributed to Jesus Christ, John and Paul in the writings of the New Testament?
Jesus Christ summarized the law as consisting of two great principles: Love of God and love of others (Matthew 22:37-40). In the Gospel of John, we also read that Jesus gave his disciples a "new" commandment: "Love each other. Just as I have loved you, you should love each other. Your love for one another will prove to the world that you are my disciples.” (John 13:34-35) Then, in the very next chapter, Christ told them: "If you love me, obey my commandments." (John 14:15) Hence, Christ clearly implied that love for (and obedience to) him was realized by loving each other. Later, this principle would be even more clearly delineated by John and Paul.
In his first epistle, John wrote: "Dear friends, I am not writing a new commandment for you; rather it is an old one you have had from the very beginning. This old commandment—to love one another—is the same message you heard before." (I John 2:7) He continued: " If we love our brothers and sisters who are believers, it proves that we have passed from death to life. But a person who has no love is still dead. Anyone who hates another brother or sister is really a murderer at heart. And you know that murderers don’t have eternal life within them. We know what real love is because Jesus gave up his life for us. So we also ought to give up our lives for our brothers and sisters. If someone has enough money to live well and sees a brother or sister in need but shows no compassion—how can God’s love be in that person?" (I John 3:14-17) He explains: "If someone says, 'I love God,' but hates a fellow believer, that person is a liar; for if we don’t love people we can see, how can we love God, whom we cannot see? And he has given us this command: Those who love God must also love their fellow believers." (I John 4:20-21)
Finally, in his famous letter to the saints at Rome, the Apostle Paul wrote: "Owe nothing to anyone—except for your obligation to love one another. If you love your neighbor, you will fulfill the requirements of God’s law. For the commandments say, 'You must not commit adultery. You must not murder. You must not steal. You must not covet.' These—and other such commandments—are summed up in this one commandment: 'Love your neighbor as yourself.' Love does no wrong to others, so love fulfills the requirements of God’s law." (Romans 13:8-10)
Is it possible that David realized that his sins against himself and others were ultimately a betrayal of God? If we assume that David wasn't an idiot and really did meditate on God's law, we have to conclude that it is very likely that he realized that his sins against Bathsheba, Uriah and his people were really sins against Almighty God. Superficially, we know that David had violated that portion of the Ten Commandments which dealt with love of neighbor - he committed adultery, he coveted that which was not his, and he was guilty of theft and murder. Moreover, it is frankly illogical and absurd to suggest that David wasn't conscious of the fact that he had broken these specific commandments. In other words, he knew what he had done! David, however, must have understood what others simply gloss over - By failing to truly love his neighbors, he had sinned against God.