At Desiring God: Psalms: Songs that Shape the heart and mind
Reading this sermon is also very helpful.
The first contrast is with the two spheres of influence on our souls. The sphere of the world/culture around us, vs. the sphere of God’s word.
One of the things that struck me was the three kinds of negative influences in this world – wicked people, sinners, and scoffers (mockers, syndical toward life and God and good things) – that Piper showed how our hearts are fascinated with wickedness (the next level of wickedness done by Islamic terrorists draws us toward the news and lingering on that incredible evil; like being fascinated with Nazi horrors or Horror movies or violent video games). Human nature is fascinated by sinners – by fornicators and adulterers (Hollywood movie stars, etc.) and those that have sex change operations – the news and gossip tabloid magazines and shows draws us to them. We are fascinated by scoffers – by TV shows like South Park and Family Guy and atheist comedians like Bill Maher in their scoffing and cynical humor, making fun of good things and mocking God.
Blessed is the man who walks not in the counsel of the wicked,
nor stands in the way of sinners,
nor sits in the seat of scoffers;
but his delight is in the law of the LORD,
and on his law he meditates day and night.
He is like a tree planted by streams of water
that yields its fruit in its season,
and its leaf does not wither.
In all that he does, he prospers.
The wicked are not so,
but are like chaff that the wind drives away.
Therefore the wicked will not stand in the judgment,
nor sinners in the congregation of the righteous;
for the LORD knows the way of the righteous,
but the way of the wicked will perish.
The Psalms are meant to be meditated upon and shape our thinking and our emotions.