A beauty and benefit of the description of spiritual growth in terms of fruit is the potent reminder that fruit does not come at once but always takes time to mature. That has special reference to our characters. The best fruit ripens naturally.
As we get older, active physical functions in the body of Christ may be denied us, but our contribution by means of our characters and spiritual influence may continue, and even increase. While our bodies decay, our souls may do the opposite. We are not to covet perpetual youth, like Peter Pan, but instead keep spiritually fresh without sterility, always giving testimony to God, our Rock.
Old age brings opportunities
The unique trials of old age provide special opportunity for increased fruitfulness of character. For most of us as we get older, our health deteriorates. We will be tempted to be self-pitying, pessimistic, frustrated and perhaps irritable. God's grace at work in us will encourage us to be thankful, optimistic on account of our living hope, contented and accepting of our circumstances.