" The psalmist says “I have set the LORD always before me.” Paul says, “We take captive every thought to make it obedient to Christ.” They speak to the need for our souls to be completely and thoroughly with God. But as both of these verses suggest, it does not happen automatically. “Set” and “take captive” are active verbs, implying that you have a role in determining where your soul rests. "

― John Ortberg , Soul Keeping: Caring For the Most Important Part of You