These instructions are an overall exhortation for the various age groups to hold to a sense of duty with regard to their conduct. But none of the instructions given here should be ignored simply because they are not addressed directly to an individual's sex or age group. For example, Paul says "girls should be discreet and modest." Does this mean, then, because it is addressed to girls that a fellow may be as indiscreet and immodest as he wants because he is male? Simply because the fellows are not mentioned does not excuse them from being discreet and modest as well. In an overall sense, God is telling all of us—parents, young people, male, female—to be sane, sober-thinking, serious about our responsibilities, exercising self-control, curbing our passions, and aiming for self-mastery.
There is a proverb that teaches: "He that rules his spirit is better than he who takes a city." Ruling one's spirit involves self-discipline. Self-discipline is willing yourself to do the right, regardless of feelings. It may not be glamorous, but it is the stuff of life.
John W. Ritenbaugh
Sanctification and the Teens