A faithful witness will not lie: but a false witness will utter lies. -Proverbs 14:5, KJV
Okay, this verse may be rather obvious, but there really is more to say.
For example, this is a reminder that you can trust people to be who they are. So, do you keep company with those who will tell you the truth, even when it hurts, or with “Yes Men” and chronic liars, those who are always only in it for themselves.
Another line of thinking: how do you respond to each of these people?
Do you lash out at the faithful witness or accept their words?
Do you treat the liar with contempt and hatred or with enough respect for the image of God in them to help protect both of you from the effects of their lies?
If you know their character, it is easier to respond. Always fall back on truth and God’s word, holding yourself and others to that standard.
There is no easy answer for how this is done, and it can depend on each instance with each person, but trusting in our Faithful Father to guide us by His Holy Spirit will be our protection and salvation.