That's quite a list! Paul is declaring that in a world of deceit, think on truth. In a world of defilement, deliberate on that which is dignified. In a world of ungodliness, reflect on righteousness. In a world of perversion, ponder purity. In a world that is hateful, concentrate on love. In a world of evil reports, contemplate that which is well spoken of. Beware of allowing the world to poison your mind with all of the evil and negativity that surrounds us continually. Instead, meditate--think with serious contemplation--upon these high and holy ideals that Paul shares here! Think on good things! This is part of what it takes to "stand fast" in the Lord (cf. 4:1).
Remember what Jesus said in Matthew 12:34,35? "Brood of vipers! How can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks. A good man out of the good treasure of his heart brings forth good things, and an evil man out of the evil treasure brings forth evil things." Jesus taught a very important truth here--one that I'm afraid many Christians do not take as seriously as they should. When we allow our minds to be filled with wicked thoughts (things that are impure, untrue, hateful, etc.), then this will affect our hearts and it will start to show in our words and deeds! If you treat your mind like a landfill, then before long it will stink! It's impossible to take garbage in and not start smelling like it.
However, on the other hand, if we only allow ourselves to meditate on those things that are true, noble, just, pure, lovely, of good report, virtuous, and praiseworthy, then those wonderful qualities will show up in our speech and actions also. Dear listeners, I plead with you to ask yourself: what am I filling my mind with? God wants us to meditate upon good things. This verse is so broad and powerful in its application. For example, this verse prohibits us from reading dirty books or magazines. It bars us from watching immoral movies. It forbids us from listening to gossip. On and on we could go. This verse also positively commands us to meditate upon the Bible. God's word meets all eight qualities mentioned here, and certainly God wants us to fill our minds with His truth. Friends, are you obeying this verse? Don't deceive yourself into thinking that you can mentally ingest a diet of filth and be unaffected. We must meditate on things that are good if we are to achieve our maximum potential for the Lord!
Paul continued in Philippians 4:9 - "The things which you learned and received and heard and saw in me, these do, and the God of peace will be with you." Paul had shown them an example of the way a faithful child of God should live. They knew Paul was a genuine follower of the Lord. In fact, some in Philippi were Christians because of what they had learned, received, heard, and seen from Paul regarding godly living. Paul demonstrated obedience from the heart. He was a great model of one who was standing fast in the Lord. He hoped the Philippian Christians would follow his example. I hope you will do likewise today also.