When I was a youth pastor in the 70s at First Baptist Church of Joliet, Illinois, we had a big kid named Dan, who one day boasted, "I can put an entire Big Mac in my mouth and swallow it whole." We said "No way!!!" So, we drove to McDonald's and bought a Big Mac for Dan.
Was this an idle boast because he wanted a free meal? Dan - who was a football player at Joliet Central H.S. - inserted the Big Mac in his mouth. That was the last we saw of it. I am certain Dan saw more of it later than he wanted. If you don't take small bits and chew your food it will not get assimilated to your physical body.
The Psalmist wrote, "Lord I love your law. I meditate on it day and night." (Psalm 119:97) Meditation is a slow-cooker, not a microwave. Meditation is like a cow chewing its cud, not a kid inhaling a Big Mac. Meditation on God-thoughts allows the Spirit to assimilate them to your spirit, and even to your physical body.
Thomas Merton says it this way. "All good meditative prayer is a conversion of our entire self to God. One cannot, then, enter into meditation, in this sense, without a kind of inner upheaval... [which results in] a liberation of the heart from the cares and preoccupations of one's daily business." (Thoughts in Solitude)
To meditate on God's thoughts in Scripture is to be self-exegeted by Scripture. Bible "study" can keep God's thoughts at an objective distance. Meditative Scripture reading is my spirit simmering in the flavors and spices of the mind of Christ. As I am studied by Scripture I am empowered by the Spirit.
Meditative praying produces inner change. I must choose this day what my meditation shall be, for so shall the shape of my heart be formed.
Tim Keller writes:
"Persons who meditate become people of substance who have thought things out and have deep convictions, who can explain difficult concepts in simple language, and who have good reasons behind everything they do. Many people do not meditate. They skim everything, picking and choosing on impulse, having no thought-out reasons for their behavior. Following whims, they live shallow lives."