Nobody grows old by merely living a number of years. People grow old by deserting their ideals. Age wrinkles the body. Quitting wrinkles the soul. (Douglas MacArthur, late 5-star American general)
MacArthur was not speaking of physical age but growth in maturity or advancement. He saw that when a person leaves his moral standard, he or she seems to deteriorate in their real self—their heart and mind. The body may weaken, the face may wrinkle, but the soul remains healthy and strong if a person maintains integrity, holding on to what is right and good.
Let perseverance finish its work so that you may be mature and complete, not lacking anything. (James 1:4) Until we all reach unity in the faith and in the knowledge of the Son of God and become mature (Ephesians 4:13).