Blessed is the man that walketh not in the council of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful.
The psalmist is giving instruction to us about how to live. Don’t get council from ungodly people. If they aren’t following Jesus, what kind of advice will they give? Don’t make unsaved people your closest friends. (If they are family, live for Jesus and be an example.) Love them and tell them of Jesus, what He has done for you. We are all sinners saved by grace. Scornful means we don’t like or respect someone or something.
Don’t spend time with people who are complainers or backbiters. Follow Jesus!