Objection 1. It would seem that sobriety is more requisite in persons of greater standing. For old age gives a man a certain standing; wherefore honor and reverence are due to the old, according to Leviticus 19:32, "Rise up before the hoary head, and honor the person of the aged man." Now the Apostle declares that old men especially should be exhorted to sobriety, according to Titus 2:2, "That the aged man be sober." Therefore sobriety is most requisite in persons of standing.
Objection 2. Further, a bishop has the highest degree in the Church: and the Apostle commands him to be sober, according to 1 Timothy 3:2, "It behooveth... a bishop to be blameless, the husband of one wife, sober, prudent," etc. Therefore sobriety is chiefly required in persons of high standing.
Objection 3. Further, sobriety denotes abstinence from wine. Now wine is forbidden to kings, who hold the highest place in human affairs: while it is allowed to those who are in a state of affliction, according to Proverbs 31:4, "Give not wine to kings," and further on (Proverbs 31:6), "Give strong drink to them that are sad, and wine to them that are grieved in mind." Therefore sobriety is more requisite in persons of standing.
On the contrary, The Apostle says (1 Timothy 3:11): "The women in like manner, chaste... sober," etc., and (Titus 2:6) "Young men in like manner exhort that they be sober."
I answer that, Virtue includes relationship to two things, to the contrary vices which it removes, and to the end to which it leads. Accordingly a particular virtue is more requisite in certain persons for two reasons. First, because they are more prone to the concupiscences which need to be restrained by virtue, and to the vices which are removed by virtue. On this respect, sobriety is most requisite in the young and in women, because concupiscence of pleasure thrives in the young on account of the heat of youth, while in women there is not sufficient strength of mind to resist concupiscence. Hence, according to Valerius Maximus [Dict. Fact. Memor. ii, 1 among the ancient Romans women drank no wine. Secondly, sobriety is more requisite in certain persons, as being more necessary for the operations proper to them. Now immoderate use of wine is a notable obstacle to the use of reason: wherefore sobriety is specially prescribed to the old, in whom reason should be vigorous in instructing others: to bishops and all ministers of the Church, who should fulfil their spiritual duties with a devout mind; and to kings, who should rule their subjects with wisdom.
This suffices for the Replies to the Objections.
Source: Summa Theologica (New Advent)