You never will be able to understand the hidden mystery of your own spiritual life and spiritual being until you use the Word of God to help you to solve the mystery. The Word of God is not only designed to unlock the human heart, so that God and the Holy Spirit may gain admission, but this key is also designed to lock the door against Satan and sin and keep them out of our hearts. Unless we daily use our Bibles to lock our hearts against evil thoughts, and wicked purposes, and sinful desires, we will find that they will steal into our hearts; and like the evil spirit that had been driven out and afterward returned and brought seven other spirits more wicked than himself, so sin and Satan will again take possession of our hearts and lock them against God and all that is good. QUESTIONS.--Are there many kinds of locks? Must there be as many kinds of keys as there are kinds of locks? Is the human heart like a lock? Does God desire to get into the human heart? With what key does He unlock it? Are the lock and its key made by the same man? Who made the human heart? Who made the key to unlock it? Can the Bible be used to lock the human heart against the entrance of sin? What are skeleton keys? Do men try false keys with which to open the human heart? What are some of the things with which they try? Is the human heart ever satisfied until unlocked by the Bible and possessed by God? [Illustration] TRAPS. UNSUSPECTING MICE AND MEN. SUGGESTION:--An ordinary mouse trap will be serviceable. The trap can be set and instead of a mouse, a child can spring the trap with his finger. The parent had better try his own finger first, to see that the trap is not too strong. A rat trap should never be tried in this way. MY DEAR YOUNG FRIENDS: You may think that possibly there was a time when wicked men did not desire to destroy others, as is so often the case in this day. Hundreds of years ago, God said, "Among my people are found wicked men: they lay wait, as he that setteth snares; they set a trap, they catch men." (Jeremiah v: 26.) [Illustration: Mouse Trap.] I suppose you have all seen traps. There are a great many different kinds. Some are very dangerous, and yet you cannot see the danger until you are caught, or until you see some other person who has been caught in the trap. Now here is a trap. I suppose that you have all seen such traps as this, and possibly have them in your own homes, to catch the little mice which destroy your food, and oftentimes do much injury.