Three dangerous underground influences on the people in your church are the movies they watch, the music they listen to, and the Internet they access. If you are a pastor, you should not underestimate what is done in private. It has an enormous unseen influence on church life. If you have a weak church, you will find that you have a strong underground that is working against the Word of God. It is often what you don't know that is hurting the church. Beware: there are mighty underground currents moving in people's hearts that are driven by their use of movies, music, and the Internet. These currents are moving silently in the church. Pastors often make a terrible mistake. They feel that these things are none of their business, when in fact they are having a profound influence on the holiness, worship, belief, and actions that are representative of that church. Often pastors are reluctant to speak to young men about the underground streams that are driven by the movies, music, and Internet they are drinking. They end up treating them like orphans. They would never let their own sons feed these streams. But, they freely allow it with those under their less-than-fatherly care.
Thomas Watson identifies the true nature of the situation – you have a "curtain" sinner in your church:
A godly man will not allow himself in secret sins. Some are more modest than to commit open gross sin. That would be a stain on their reputation. All will not sin on a balcony—but perhaps they will sin behind the curtain!
But a godly man dare not sin secretly, for he knows that God can neither be deceived by our subtlety, nor excluded by our secrecy. He knows that secret sins are in some sense worse than others. They reveal more deceit and atheism. " "He knows the secrets of every heart," Psalm 44:21.
But the curtain-sinner thinks that God does not see: "Have you seen what the leaders of Israel are doing with their idols in dark rooms? They are saying—The Lord doesn't see us!" Ezek. 8:12. How it provokes God, that men's atheism should give the lie to His omniscience! "He who formed the eye—shall He not see?" Psalm 94:9.
J.C. Ryle in Thoughts for Young Men speaks of the dangers that lurk, especially for young men:
The devil uses special diligence to destroy the souls of young men, and they don't seem to know it.
Satan knows very well that you will make up the next generation and therefore he employs every trick to make you his own. I would not have you to be ignorant of his schemes.
You are those on whom he puts his choicest temptations. He spreads his net with the most watchful carefulness, to entangle your hearts. He baits his trap with the sweetest morsels, to get you into his power. He displays his wares before your eyes with his utmost ingenuity, in order to make you buy his sugared poisons, and eat his accursed treats. You are the grand object of his attack. May the Lord rebuke him, and deliver you out of his hands.
Young men, beware of being taken by his snares. He will try to throw dust in your eyes, and prevent you seeing anything in its true colors. He would eagerly make you think that evil is good, and good is evil. He will paint, cover with gold, and dress up sin, in order to make you fall in love with it. He will deform, and misrepresent, and fabricate true Christianity, in order to make you take a dislike to it. He will exalt the pleasures of wickedness--but he will hide from you the sting. He will lift up before your eyes the cross and its painfulness– but he will keep out of sight the eternal crown. He will promise you everything, as he did to Christ, if you will only serve him. He will even help you to wear a form of Christianity, if you will only neglect the power. He will tell you at the beginning of your lives, it is too soon to serve God--he will tell you at the end, it is too late. Oh, do not be deceived!