Psalm 1:1-3 (NKJV)
Blessed is the man who walks not in the counsel of the ungodly, nor stands in the path of sinners, nor sits in the seat of the scornful; but his delight is in the law of the Lord, and in His law he meditates day and night. He shall be like a tree planted by the rivers of water, that brings forth its fruit in its season, whose leaf also shall not wither; and whatever he does shall prosper.
There is an interesting word picture in this verse of what happens to people who digress into various stages of sin. First of all, in the course of a normal life's activities (walk), they will begin to listen to what the world has to say (counsel of the ungodly). As initial shock and blushing turn into curiosity and amusement, they will begin to hang out (stand) in the wrong places inviting temptation from a crowd (sinners) bent on just "having a little fun." Finally, after having joined in (sit), their hearts will darken and they will begin to justify their behavior by mocking (scorn) those who aren't so "liberated."
This verse says you will be blessed if you don't fall into this trap. Then we are reminded that being righteous is not all about avoiding sin but it is about having delight in the things of God. I like the picture of a fruitful, deep rooted tree next to a stream.
Great memory verse!