The book of Proverbs provides insight about how to be wise (Proverbs 1:1-7). Proverbs is not primarily a set of rules to follow, but practical wisdom that can be applied to everyday life. This book will teach you and your children to avoid people and situations that will bring harm. For example, verses 1&2 of Chapter 18 help identify a person who is unfriendly and not to be trusted.
Each verse has two lines. The second line compliments the first. So in verse 1 we learn that a person who is unfriendly is selfish. That makes sense. But then in the second line of this verse we find a clue that identifies this selfish person; they start foolish quarrels.
An unfriendly person pursues selfish ends
and against all sound judgment starts quarrels.
In verse 2 the pattern is repeated. In the first line we learn that fools, those who despise wisdom, have no interest in understanding. This is confirmed by line 2 which teaches that these fools delight in stating their own opinion.
Fools find no pleasure in understanding
but delight in airing their own opinions.
In real life this means someone who starts arguments which appear to have no point and is constantly giving his own opinion is someone who is unfriendly and has no interest in truth.
This is huge. It means someone who is always pushing an agenda and always talking about their ideas is someone that is not to be trusted whether they appear to be friendly or not. You could learn this by experience or you can learn this by trusting the insight of the Holy Spirit. Learning by trusting the words of the Spirit is the much less painful approach!
Whether someone is 7 or 17 or 37, if they are string up trouble and talk about their own ideas all the time, they are not friendly and have selfish desires. This is valuable insight for any age!