I've been listening to Mike Reeves giving an intro to Psalms, and particularly on Psalm 1 and 2. It was very good! Here's a sketch of some of it.
Psalm 1 and 2 should be held together - they are two halves of one Psalm really.
Who is the man of Psalm 1? Is it us? Should we be meditating on the law day and night? Should we avoid too close a walk with sinners? Well yes, but that's not the point.
Psalm 1 should be understood in the light of Deuteronomy 17 - the King is the one who should be characterised by delighting daily in the law of the Lord. The man of Psalm 1 is referred to as the king in Psalm 2v6. The ultimate king is Jesus, he is the King of Kings. He is the subject of these Psalms (and the focus of the whole book in fact).
So Psalm 1 - the difference between the blessed man and the wicked man. Psalm 2 - the battle between them... Jesus has the victory!
What's the tree about in Psalm 1? Well, if you understand that the 5 books of the Psalms act act a bit like commentaries on the first 5 books of the Bible respectively, you'll see the tree is the tree of life. Where else do we see this? In the new creation.
The man is compared to the tree - how is Jesus like the tree of life? He is the one who gives life - the life giving Spirit and eternal life.
These psalms begin and end with blessing and here we find the application for us.
Psalm 1v1: "Blessed is the man..."
Psalm 2v12: "Blessed are all who take refuge in him."
How are we blessed by God? Based on how good we are? Based on how we remain distinct from the wicked? Based on how much we read our Bible? No - by taking refuge in THE man - Jesus Christ.
It just makes sense doesn't it! Wonderful!