Identify people by the way they act
“Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves. You will recognize them by their fruits. Are grapes gathered from thorn bushes, or figs from thorn bushes? So, every healthy tree bears good fruit, but the diseased tree bears bad fruit. A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire.Thus you will recognize them by their fruits. (Matthew 7:15-20)
It’s very simple to identity not just false prophets but also people in general. Some of them may lie that they are the good guys but their actions which are evil are something they won’t be able to hide for too long. You just need to keep your eyes open to notice the fruit of their actions. Once you realize that their workings are sinful immediately keep away from such wicked people and thus save yourself from trouble.