The Bible instructs us about how to do many of the works we carry out as Christians. It tells us how to worship, how to become a member of God's family, and how to carry ourselves as Christians. We are also told to avoid certain things, such as lying, idolatry, and fornication. These all refer to works a Christian should or should not do. But much of being a Christian involves the mind. The Old Testament forbids murder, adultery, and other sinful acts. Jesus, in the Sermon on the Mount (Matthew 5), goes a step further. He says that a person who is angry with his brother for no reason is sinning and one who lusts after a woman has committed adultery with her already in his heart.
So what do we think about to help us on our way as Christians? Philippians 4:8 plainly answers this question: "Whatsoever things are true, whatsoever things are honest." This rules out gossip, and things without proof. Dwelling on these things can be harmful to us. Have you ever assumed something bad about someone? As time goes by, you begin to think that person is worse and worse, until you begin to let it rule your mind. Then you talk to the person and find that what you thought about this person was not true. You then wonder why you spent so much time thinking about something so stupid. What good has it done you as a Christian?
"Whatsoever things are just, whatsoever things are pure." This refers to things that are according to God's law. Job 4:17 says that we will never be more just or purer than God. Therefore, God is our example of how to be just and pure. Romans 1: 1-7 says that the just shall live by faith.
"Whatsoever things are lovely, whatsoever things are of good report." This refers to things that are worthy of love and good news. This means we need not dwell on bad news or hateful things, but to remember how good life is (you have to admit it's much better than it was for early Christians). If we think on the bad things in life, it will never be enjoyable, and more important, it will hinder our work as Christians. We have been blessed with the hope of heaven, which is enough to outweigh all bad experiences in our minds. I Timothy 6:6 says that godliness with contentment is great gain. Maybe we shouldn't think about how hard it is to be a Christian, but about what we gain from it.
"If there be any virtue, if there be any praise, think on these things." This kind of summarizes the verse, encompassing all of the previous points.
So why do we have to think on these things? Proverbs 4:23 says that we are to control what we think because our minds deal with the issues of life. When we read a book about how to do something, we expect to put it to use in our lives. When a situation in which the knowledge can be used comes along, we usually do it without thinking. This is how our minds work with everything. I'm sure you've heard the expression, "What you put in your head is what's going to come out." Thinking on the things taught in Philippians 4:8 will make us better Christians. Why? Never forget this truth--God knows our thoughts as well as our actions.