Sin is a transgression of God's law (1 John 3:4; Romans 4:15). Sin by its very definition is against God because to sin means either to violate God's prohibitive commands or to omit practicing His positive commands (James 4:17). Since God's law is a reflection of His holy nature, to sin by transgressing His law is to offend Him personally. This point is illustrated for us in the narratives concerning David's sin of adultery and murder as well as the temptation of Joseph by Potiphar's wife (Psalm 51:4; Genesis 39:9). Although adultery and murder are clearly sins against other people, both David and Joseph view them to be primarily against God Himself.
Why are all sins ultimately against God?
We sin against others by doing to them what God has forbidden or by failing to do to them or for them what God has commanded (Matthew 22:39; James 2:8). The commands do not come from others but from God. Therefore, the sin is first and foremost against Him. An analogy can be seen in the arena of criminal law. When a person commits a crime against another person, they have violated not only that person but the law of a state or country primarily. This is why it is the government, not the individual who was harmed, who is named in the legal caption (e.g. The State of Florida vs. Mr. Jones). The government prosecutes and the government executes judgment. Likewise, when we sin against others, we are transgressing, not their law, but God's law. Therefore, it is God who is the rightful prosecutor and judge (Acts 17:30–31). God has appointed His Son, Jesus Christ, to carry out this judgment. It is through believing in Jesus Christ's perfect life, sacrificial death, glorious resurrection, triumphant ascension, and sovereign reign that we are saved. It is through believing that God has washed us clean of every sin we have committed and will commit against Him based on the substitutionary atoning death of His Son that we escape God's just wrath against sin (1 Thessalonians 1:9–10).
Just as every sin is ultimately against God, every sin can be ultimately forgiven because of God's gift of Jesus Christ (Matthew 26:28; John 4:10; Ephesians 2:8–10).
What is sin?
Does God hate sin? Why?
Does my private, personal sin affect others?
How do I receive forgiveness from God?
How can I get right with God?
Truth about Sin