I have previously written an article about 1 Peter 3:7, the Bible verse that includes the phrase “a weaker vessel” [here]. Since writing this article, however, I’ve come across a few references in Greek papyri where women are called “weak” (asthenēs). In these papyri, women use the adjective for themselves hoping to elicit pity, or hoping to ingratiate themselves, while seeking justice from men. A.L. Connolly comments on several of these legal petitions and notes that appealing to a woman’s frailty (asthenēs) “had become commonplace in the rhetoric of petitions.”
Peter calls wives “weaker vessels” because he wants husbands, not necessarily to pity them, but to be more understanding with their wives. Ancient women were, with few exceptions, disadvantaged economically, legally, and politically. They had less power and fewer rights in society than men.
In 1 Corinthians 1:27b, Paul used the Greek word asthenēs to mean weakness in society: “God chose the weak of this world to shame the strong.” The context of social weakness is given clearly in the preceding verse, 1 Corinthians 1:26, where Paul wrote that not many of the Corinthian Christians were (1) wise according to the flesh: they did not have the wisdom that came with an advanced education; (2) not many were mighty: they did not have social clout or influence; (3) not many were well-born: they did not come from elite families with the social advantages of wealth, a name, and powerful connections.
Peter probably had in mind the social disadvantages that ancient women faced when he used the words “weaker vessel.”
However, asthenēs is used many times in the New Testament to mean weak, sick and infirm. Did Peter have physical weakness in mind? Interestingly, Paul, who readily admitted to his own weakness, used the word asthenēs many times to mean physical weakness. He used the comparative form of asthenēs (= “weaker”) in 1 Corinthians 12:22 where he wrote, “the members of the body that seem to be weaker are indispensable.” Peter likewise uses the comparative form of asthenēs (=”weaker”) in 1 Peter 3:7.
Physical weakness is not a disadvantage in the body of Christ, and it need not be a disadvantage in marriage.
Honour and Mutuality
Neither Peter or Paul use the word “weaker” to insult or diminish anyone. In fact, they do the opposite. Like the women seeking justice, Peter uses the word “weaker” for its rhetorical effect, and he juxtaposes the phrase “weaker vessel” with the phrase “bestowing honour”. Peter wants husbands to regard their wives with honour and not consider them, or treat them, as social inferiors.
It was not unusual to hear women being called “weak” or “weaker” in the first century. On the other hand, some may have been surprised to hear Peter tell husbands to honour their wives. Furthermore, Peter gives the reason why husbands should honour their wives: because a Christian couple are co-heirs of “God’s gift of new life” (1 Pet. 3:7 NLT). Being co-heirs is a strong basis for mutuality and equality in marriage.
I’m not bothered that Peter called wives “weaker”, considering it was part of the rhetoric of petitions. Moreover, I’m delighted that he appealed to husbands to treat their wives with honour and understanding, and to acknowledge them as co-heirs. It seems Peter was advocating for justice in marriage.
 “30. ‘The Weaker Sex'”, G.H.R. Horsley with A.L. Connolly, New Documents Illustrating Early Christianity: A Review of the Greek Inscriptions and Papyri in 1979, Volume 4 (The Ancient History Documentary Research Centre, Macquarie University, 1987), 131-133, 132.
 These socially disadvantaged Corinthians were the ones who God selected, and he used them to shame the wise, the mighty, and the ones “belonging” to society. Read 1 Corinthians 1:18-30; it’s a remarkable passage of scripture.
 The entry on asthenēs in the LSJ Greek-English Lexicon is here. It gives the primary meanings as “without strength” and “weak”, and lists other kinds of weaknesses, not just physical or bodily weakness.
 Note that Peter does not say that women are “weak”. Rather, his meaning is that wives are “weak-er” than their husbands.
 Peter writes that the Christians in Asia Minor should also honour the emperor (1 Pet. 2:17).
Submission and Respect from Wives in 1 Peter 3:1-6
Submission and Respect from Husbands in 1 Peter 3:7-8
Fear or Respect in Christian Marriage?
Equality and Unity in Ministry in 1 Corinthians 12
Protecting the Weaker Sex