See Psalm 101:1–3
David is speaking about a man who has a heart for God. The “blameless heart” loves God first above everything else, even before self. But the blameless man is warned to live thoughtfully. Virtue can be attacked and compromised. “I will have nothing to do with evil.” We are cautioned to do even more because the threat to our integrity is real and dangerous: “Flee from sexual immorality” (1 Corinthians 6:18), “Flee from idolatry” (1 Corinthians 10:14), “But you, man of God, flee from all this, and pursue righteousness, godliness, faith, love, endurance and gentleness. Fight the good fight of the faith” (1 Timothy 6:11–12).
Flee from those things that will weaken or harm you. Flee from everything that will separate you from God. Instead, be strong in the Lord (Ephesians 6:20) because you need to be. Be prepared and armed because the world will do its best to weaken and disarm you, destroying your capacity to “fearlessly make known the mystery of the gospel” (Ephesians 6:19).
–Eric Kampmann, Signposts