The apostle Paul recognized the incredible power of our thought life. He understood that the way we think determines how we feel and how we live. When we guard our hearts with right thinking, we develop healthier attitudes that lead to righteous living. For this reason, in Philippians 4:8, Paul prescribed an inventory of virtues to occupy the believer’s mind: “Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things.”

 What does it mean to think on whatever is pure? According to one commentary, the words think on or think about mean “to ponder, to give proper weight and value to, and to allow the resultant appraisal to influence the way life is to be lived” (Motyer, J. A., The Message of Philippians, InterVarsity Press, 1984, p. 212). The word pure here means “holy” in the sense of “moral purity.”

 Thinking on whatever is pure entails filling our minds with thoughts that are innocent, virtuous, clean, not contaminated by anything evil, and free from every defilement. Pure thinking should infuse every area of our lives, including what we watch, read, and do. Our thoughts of a sensual nature, morality, ethics, spirituality, and worship all need to be characterized as pure. Thinking about whatever is pure will lead us away from sin, guilt, and shame and closer to God.

 Jesus said it’s not exterior things that make us impure but what’s on the inside—that which comes out of the heart: “It’s not what goes into your body that defiles you; you are defiled by what comes from your heart” (Mark 7:15). We must hide the pureness of God’s Word securely in our hearts to keep from sinning against God (Psalm 119:11). We do this by reading His Word, memorizing it, and meditating on it day and night.

 The psalmist declared, “The words of the LORD are pure words, like silver refined in a furnace on the ground, purified seven times” (Psalm 12:6, ESV; cf. 119:140). Psalm 119:9 asks and answers, “How can a young man keep his way pure? By guarding it according to your word” (ESV). Continually reflecting on the Word of God is one of the most valuable ways we can guard our hearts and ensure we are thinking on whatever is pure (Psalm 19:8).

 To consistently think on whatever is pure, believers must “take captive every thought to make it obedient to Christ” (2 Corinthians 10:5). James teaches, “To the pure, all things are pure, but to those who are corrupted and do not believe, nothing is pure. In fact, both their minds and consciences are corrupted” (James 3:17, ESV).

 Paul taught the Ephesians that, before salvation, their thoughts were “full of darkness” (Ephesians 5:8). The unsaved wander far from God because their minds are hardened and closed to Him (Ephesians 4:18). Unbelievers have “no sense of shame. They live for lustful pleasure and eagerly practice every kind of impurity” (Ephesians 4:19, NLT). But Christians “throw off the old sinful nature and former way of life, which is corrupted by lust and deception,” and allow the Holy Spirit to renew their thoughts and attitudes (Ephesians 4:22–23, NLT).

 Paul’s encouragement to think on whatever is pure has the goal of producing purity of thought, purpose, words, and actions. To the spiritual leader, Paul said, “Keep yourself pure” (1 Timothy 5:22). The apostle desired to present his spiritual children “as a pure bride to one husband—Christ” (2 Corinthians 11:2, NLT).

 The apostle John also urged God’s children—those who longed to see Jesus face to face—to “keep themselves pure, just as he is pure” (1 John 3:3, NLT). Whenever we find ourselves drifting from God, we ought to pray like David, “Cleanse me with hyssop, and I will be clean; wash me, and I will be whiter than snow. . . . Create in me a pure heart, O God, and renew a steadfast spirit within me” (Psalm 51:7–10). The Christian’s entire way of life ought to be a never-ending quest to stay pure, “for he chose us in him before the creation of the world to be holy and blameless in his sight” (Ephesians 1:4)