This post is the 3rd in a series on the Biblical qualifications for a pastor. In this post, I’ll focus mostly on getting to what I think Paul meant when he used this word. In the next post on this topic, I’ll try to flesh out some application.
A Christian minister must never be a man of excess. Νηφάλιος can refer not only to a person’s temperance with reference to wine consumption but also to a general self-control and moderation when it comes to other potential indulgences.
Other occurrences demonstrate the word’s broader field of reference. For instance, a passage in Philo reads; “But if reason be able to purify the passion, then neither when we drink do we become intoxicated, nor when we eat do we become indolent through satiety, but we feast soberly [νηφάλιος] without indulging in folly.” The final “but” statement provides a contrast both to intemperate drinking and intemperate eating, showing an accepted usage of νηφάλιος that encompassed more than simply a person’s wine intake. A man demonstrates that he is νηφάλιος not only by the amount he drinks, but by the amount he eats. Nor is the word’s range of usage limited to discussions of what people put in their mouths. Again, Philo’s usage underscores this fact:
The Greeks celebrate Anaxagoras and Democritus, because they, being smitten with a desire for philosophy, allowed all their estates to be devoured by cattle. I myself admire the men who thus showed themselves superior to the attractions of money; but how much better were those who have not permitted cattle to devour their possessions, but have supplied the necessities of mankind, of their own relations and friends, and have made them rich though they were poor before? For surely that was inconsiderate conduct (that I may avoid saying that any action of men whom Greece has agreed to admire was a piece of insanity); but this is the act of sober men [τοῦτο δὲ νηφάλιον, literally “but this (act) is sober”†], and one which has been carefully elaborated by exceeding prudence.
This passage speaks of temperance as wisdom in decision-making by one who knows how properly to balance priorities and obligations. Apparently, a man can be called intemperate because of the imbalanced way in which he pursues philosophy. In contrast, rightly ordering one’s life to provide financially for friends and relatives is sober-minded behavior. These essentially contemporary examples demonstrate a wider usage of the word is possible, and I would argue that it is the wider use that is in view in 1 Timothy 3:2. Paul will isolate and address wine consumption specifically when he specifies that the overseer must not be a “drunkard.” Here, with the word “temperate,” the idea seems to be broader.
The Christian minister must avoid excess. The Pastorals teach that asceticism is wrong and that God’s good gifts are to be enjoyed, but, one who exhibits a self-indulgent spirit of excess cannot provide the self-sacrificing, sober-minded leadership that God’s people need.
 Allegorical Interpretation 2:29. Here the neuter singular of νηφάλιος is used adverbially, but the context is still illuminating for the normal use of the adjective.
 On the Contemplative Life 1:14.