Happy is the man who, does not walk, stand, or sit with specific kinds of people. I take that to mean that we are supposed to watch who our friends are. When we distance ourselves from those we know are not living a "righteous" life, our walk with the Lord gets happier. And if we can find like-minded people to accompany us on our travels through this world we will benefit even more. It further says that to be happy this persons delight is in the law (Word) and he meditates on it day and night. The Bible says that the Word is a lamp for my feet and a light for my path (Psalms 119:105). It will guide us through that world if we will meditate on it. The blessed person is then like a tree planted (rooted) by a river, growing and producing fruit in the right season. That person shall prosper and they shall not whither. That doesn't mean they won't die, it means that their testimony will remain strong in the world and not fade. I pray that some day I will be the blessed person God wants me to be.
"Blessed is the manThe Drawing:
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." ~Psalms 1:1-3