The first Psalm speaks of a happy man. This man is happy because he does no wrong and because he knows God through His word.
Now, if you think about things correctly, you’d realise that this Psalm is not talking about any of us. As Paul say, ‘We all like sheep have gone astray’.
Besides our personal failure to fulfil any of the requirements of happiness as described by this Psalm, there is another difficulty.
The Psalm is only talking about a singular male person. In Psalm 32:2, where it talks of the happiness of the ‘man’ to whom the Lord does not impute sin, the word ‘man’ there is actually the Hebrew word for human beings, irrespective of age or gender.
In Psalm 1, as I said, the word ‘man’ means male, a singular male. The singular male is set in opposition to the many wicked, the many sinners.
In Luke 24:43, Jesus says that the whole Old Testament foretells him. The Psalms are essentially about our Lord Jesus Christ.
Jesus is the happy man because he alone fulfilled all the requirements for happiness. He did that for his people. He worked righteousness for them.
Again, when He meditated on the law of the Lord, he saw there his job description. He would live that good life, but as the lamb of God who takes away the sins of the world, he also became the sinless sin-bearer. Jesus willingly received the condemnation that our sins deserve. The Old Testament temple sacrifices pointed to the death of Jesus for his people.
That is why Psalm 1 can talk about the way of the righteous. Jesus is the way (and the truth. and the life). The Lord God acknowledges that way, and for Jesus’ sake He justifies those sinners who trust themselves to the Son of God who died and rose to save his people from there sins.
It is through this happy man, Jesus, that the happiness promised to Abraham comes to the nations. By means of the good news of Jesus, miserable sinners can have life instead of death, and joy instead of bitterness. Jesus is that fruitful, flourishing tree — the tree of life.