2Sam 10-11, 1Chron 20 What do you do as a king in the spring of the year? That is the time for battle, but David doesn’t go to war but instead lolls about on the roof of his palace. Why isn’t he off about with his men? He is bored. And boredom is the very thing that Satan desires. Idle hands are the devil’s workshop. David’s eyes are not on his men but on the lust of his eyes, and so the sight of Bathsheba only encouraged his lust, and so he did just as Eve, he saw, and he took. If that wasn’t sin enough, David then tried to cover up his sin by seeking the murder of Bathsheba’s husband, the humble and honest Uriah the Hittite. Today we call it an affair, but God calls it just what it is: adultery, and that is sin #1 because it puts lust in place of God. And just like that, David’s look ended up with taking a life that was pure and holy and tainted it with sin.
Charles Spurgeon put it like this: “As soon as ever we are conscious of sin, the right thing is not to begin to reason with the sin, or to wait until we have brought ourselves into a proper state of heart about it, but to go at once and confess the transgression unto the Lord, there and then.”