It's a verse of Scripture that almost everyone can quote - especially in the KJV. If David were alive with us today, and you and I had the choice opportunity to ask him how he became a "man after God's own heart," what do you think he would say? What was the secret of his spiritual greatness? Fortunately we don't have to guess. He tells us one of the richest secrets anyone can know. In this one short verse David stands up and says, "Here's the approach I took to becoming a man after Gods own heart."
I want to know this. I don't have time to waste on fads and trends and things that simply don't work. I want a Godly heart. A Godly life outwardly comes from a Godly heart inwardly - "I have stored up your work in my heart." I'm convinced this is exactly what Jesus had in mind when, though using different words, He drilled down into the same truth about the Word stored up in the heart - John 15:7-8 - "If you abide in me, and my words abide in you, ask whatever you wish, and it will be done for you.  By this my Father is glorified, that you bear much fruit and so prove to be my disciples."
These are amazing words. They describe a spiritual root - God's Word - abiding inside my body, rather than on the pages of my Bible. Both David and Jesus are talking about knowing the Word by heart. And both say there is no possibility of transformation without this process. I can't abide in Jesus just by trying to imitate Him. They aren't just describing a "What Would Jesus Do?" approach. That's a spiritual cop-out. The life of our Lord can't be mimicked from the outside. It's His words abiding in us that create His life, by the Holy Spirit, through us.