In this section (Numbers 25:1-8) we see some lessons about sin, and helps us to understand why sin is aptly labeled "cosmic treason." First of all because sin is contempt toward God. That's pictured in the fact that this occurs right as the people are assembled before God, and this man acts this way right in the sight of everyone. It's contempt. Now most people don't believe that sin is contempt toward God. We have more polite terms like "It was a mistake," "I messed up." At the heart of it is contempt; a contemptuous attitude toward the person and the work of God, toward His holiness and righteousness in particular.
So next time you're talking with that friend and that family member and you're discussing sin and they start to use language like "I messed up," just say to them, "No, I think you have contempt toward God." And do you know what they will say? They'll say something like, "No I don't. When that happened I wasn't even thinking about God!" And you just say "Exactly...exactly."
That's the nature of the contempt. It's not retaining the knowledge of God in our life and in our actions, in our heart, in our affections. It's the suppressing of that knowledge of God as Paul describes it in Romans 1. That's what the contempt is. We are to be consumed with love for God and worship of God, and because we're sinners and misshapen in our sin, the contempt manifests itself in the least as not thinking about God, but delighting in the sin. That's why sin is treasonous.
In Genesis 3:15, the Lord promised to put enmity, promised to put hostility between the seed of the woman, namely Christ and her descendants, and the serpent himself. We read quite plainly and quite accurately and helpfully in Romans 8 that the carnal mind, the mind set on the flesh, is hostile to God. Somehow the hostility has entered into us so that we are now contemptuous of God, we are alienated from Him, and we are estranged from Him, and we are at enmity not with the serpent, but with God. Treasonous.
James 4 tells us, "Do you not know that friendship with the world is enmity with God? Therefore whoever wishes to be a friend of the world makes himself an enemy of God" (James 4:4).