SPIRITUAL MUSCLE
I was visiting Pink at the nursing home. His legs had been like sticks, because he could have no therapy until his sore healed. Skin hung down, and he had no muscle. But now he is getting rigorous therapy; the skin has tightened, and muscle is now beginning to form.
That’s what edification is. It is the building of spiritual muscle, primarily through learning the contents and meaning of the Word of God and doctrine. It involves encouragement, serving, and training to do the will of God. It is "growing in the grace and knowledge of our Lord Jesus Christ," as Peter does in 2 Peter 3:18.
The Church program, body life, and educational ministries are the gymnasium. If don’t work out, you don’t build muscle. You atrophy. Many Christians have spiritual legs that are sticks with skin hanging down. And it doesn’t bother them one bit. They are not willing to apply their minds to study; they will never get better in this life.