Paul was himself in a happy mood.
Very beautiful, to my mind, is the sight of “Paul the aged” immured in his prison at Rome, likely by-and-by to be put to death, but calm, quiet, peaceful, and joyful.
Contentment in all states is not a natural propensity of man.
So you have no need to teach men to complain; they complain fast enough without any education.
Now, contentment is one of the flowers of heaven, and if we would have it, it must be cultivated. It will not grow in us by nature; it is the new nature alone that can produce it, and even then we must be especially careful and watchful that we maintain and cultivate the grace that God has sown in it.
Many times, it seems that God doesn’t come through for us until we can’t take one more step. Then he provides at just the right time, strengthening us. The lesson of contentment is most effectively learned during times of suffering or need.