2 Samuel 13:3
“Now Amnon had a friend named Jonadab, the son of David’s brother Shimeah. Jonadab was a very shrewd man”.
This friend of Amnon's prompts him to sin in a horrible way. This sin was against his half sister. He raped her. Unfortunately David didn't discipline him to avenge his daughter. So, the girls brother, Absalom had him killed. This may have been the proper consequence David should have doled out.
All of this because of Jonadab's advice. The bible speaks of having good friends. Ones that will encourage us in the right path. It also warns against those will will lead us to evil. Proverbs 12:26 says, "One who is righteous is a guide to his neighbor, but the way of the wicked leads them astray." Jonadab was the latter. He gave advice on how to rape the sister.
I can recall my parent telling me not to have a particular friend. I've told that to my own daughters. I can recall two bad friends that introduced me to bad habits that I would have never done on my own. I continued those practices once that friend was gone. They passed evil on to me and I adopted it as my own. The first happened around 3rd grade and the other happened at 7th or 8th.
As far as we can tell Jonadab received no consequences. Nor did the two bad friends in my case. The latter bad friend in my case attempted to friend me on facebook a decade ago. I ignored it. I can't recall associating with him after jr high. My recollection of him was his bad influence. I wanted nothing to do with him. Even 45 years later.
Fortunately, I never got in trouble with either bad habit. I could have. Even though I wasn't a christian. I believe I was younger than the age of accountability. God must have been looking out for me. I had a praying mother.
We are to have good friends and to be the good friend. They should affirm our faith. These are our inner circle. They should draw us closer to Christ. And we them. We should be encouraging them and making them better.
Are we to associate with unbelievers? Sure. In I Corinthians 5:9, 10, Paul makes the case to do so. They wouldn't be close friends, but enough for us to be a witness of Christ. That's how we share Christ with coworkers and neighbors. If they drag us down, then we need to give space.
Lord, I thank You for my friend group. I have been so blessed by brothers in Christ. Thank You for helping in my youth and keeping me out of trouble. The story of Amnon and his sister is a tragic one. Thank you for including it as a warning.