"They went all the way across the island to Paphos, where they met a certain magician named Bar-Jesus, a Jew who claimed to be a prophet. He was a friend of the governor of the island, Sergius Paulus, who was an intelligent man. The governor called Barnabas and Saul before him because he wanted to hear the word of God. But they were opposed by the magician Elymas (that is his name in Greek), who tried to turn the governor away from the faith.

Then Saul — also known as Paul — was filled with the Holy Spirit; he looked straight at the magician and said, “You son of the Devil! You are the enemy of everything that is good. You are full of all kinds of evil tricks, and you always keep trying to turn the Lord's truths into lies! The Lord's hand will come down on you now; you will be blind and will not see the light of day for a time.”

At once Elymas felt a dark mist cover his eyes, and he walked about trying to find someone to lead him by the hand."

(Acts 13.6-11 GNB)

Those who are full of evil tricks and those who turn the Lord's truths into lies - be wary of them. The world is full of them.

As a child of God, it it crucial for me to study well the Lord's truths and to apply these truths in my life and be vigilant not to fall into evil tricks and lies. The big ones may be a bit more visible, but the small ones that may seem harmless - these will will lead to infestation, if I do not mitigate them from early on.

At the other end of the spectrum, there are also seemingly religious people who use religion to turn people away from the Lord. I ought not be like them, either.

See:
Infestation
Whitewashed tombs