An overseer, then, must be above reproach, the husband of one wife, temperate, prudent , respectable, hospitable, able to teach…
1 Timothy 3:2 (emphasis mine)

A spiritual leader in the church must not be ruled by his emotions or be easily stirred up. He is responsible to handle the spiritual affairs of the church with wisdom and consistency.

“This quality is the result of being temperate. The prudent man is well-disciplined, and knows how to correctly order his priorities. He is a person who is serious about spiritual things. That does not mean he is cold and humorless, but that he views the world through God’s eyes. The realities that the world is lost, disobedient to God, and bound for hell leave little room for frivolity in his ministry. Such a man has a sure and steady mind. He is not rash in judgment, but thoughtful, earnest, and cautious.”1

“The term covers a range of meaning (prudence, moderation, sobriety), but gives the general sense of control over the behavior and the impulses and emotions beneath it. Although it appears here as a requirement for leadership (Titus 1:8), it was expected of all believers (2:9, 15; Titus 2:2, 4, 5, 6).”2

1 MacArthur, J. F., Jr. (1995). 1 Timothy (p. 106). Chicago: Moody Press.
2 Towner, P. H. (2006). The Letters to Timothy and Titus (p. 252). Grand Rapids, MI: Wm. B. Eerdmans Publishing Co.