What does the Bible say about holiness and sin?

Holiness, as described in Scripture, is fundamentally about being set apart for God's purposes. In Joshua 6:19, the Lord specifies that certain items are sacred and must go into His treasury, illustrating that some things are designated for divine use. Achan's sin wasn't merely about coveting material possessions; it was about taking what was holy and treating it as common. This principle is crucial in understanding sin. All sin is ultimately a violation against God, as David expressed in Psalm 51 when he said, 'Against you and you alone have I sinned.' Thus, holiness and sin are intertwined in the sense that every act of sin is a disregard for God's holiness and a claim of ownership over what belongs to Him.