This is the original Biblical definition of modesty, and it is not what you're told.
|"Likewise, I call for women to adorn themselves modestly, not with braided hair, gold, pearls, or expensive clothing, but rather with good works, as is proper for women who claim holiness."
1 Timothy 2:9-10
The rest of Chapter 2 is Saint Paul's defense of the Magisterial Priesthood as a male institution. For those who wonder why Orthodox Christianity (Roman Catholic, Eastern Orthodox, Coptic Orthodox, Jerusalem Orthodox, and Antiochian Orthodox groups) do not ordain women to Priesthood, read the rest of 1 Timothy 2.
Back to the matter at hand, Biblical modesty is not what popular culture and Fundamentalist preachers will tell you today. In 1 Timothy 2:9-10, we have essentially a dictionary definition of what "modesty" meant in the 1st Century context in which the New Testament was written. Based on original context, modesty has nothing to do with how much skin is shown (as that if anything signifies vulnerability, Matthew 25:36), but rather, it has to do with avoiding displays of wealth or class.
Of course, the definition of appropriate clothing is contextual. At work, just follow whatever company policy says. A sporting event of any kind is different from a work shift, and a concert by the school choir is different from both. A beach or swimming pool is different from all of the above.
In the context of a beach or pool, even if you are a female, do whatever makes you comfortable. Holy Writ does not say that males, and only males, are ethically in the clear to show our back and belly when swimming or sunbathing.
Objection 1: "Occasions of lust."
This popular objection ignores the difference between attraction and lust. Attraction is a biological response to beauty. Lust is the greedy and glutinous obsession therewith. When one has a moment of attraction, it is that person's responsibility to see that it does not fester and progress to become lust.
Objection 2: "You are ignoring Galatians 5:17 and 1 John 2:16."
No, those verses are both about all sins, or at the very least about actual lust and not mere attraction. Again, attraction is not a sin unless it becomes lust.
Objection 3: "Go back and reread Romans 7:15-25."
That passage, while somewhat esoteric, is considered by most scholarly commentators to be anecdotal. Paul is here using "the flesh" as an idiom for his former self. His former self who practiced greed and gluttony while persecuting the Church for a paycheck, that is. Although he considers himself an extreme example, Saint Paul suggests that other Christians, many if not most, have similar struggles. His advice is to power through the struggle with the former self, holding on to conversion at all costs.
Objection 4: "The whore in Revelation 18 symbolizes your belief that attraction is not automatically lust!"
No, she symbolizes the City of Rome. The reference to Rome is obvious to every Biblical scholar.
The Latin word for "city" is Urbs, and it is a grammatically feminine noun. The same is true of ΠOΛIΣ in Greek, and so the Classical grammar makes it obvious why Rome (or any city) would be personified as a woman.
Roman Emperors Caligula and Nero were the worst of the 1st Century when it came persecuting Christians. (Emperor Diocletian made eliminating Christianity his very top priority, but he was in office in the late 3rd Century.) The book at the very back of the Bible, Revelation, was probably written during the reign of Nero. Chapter 18 is a warning that the City of Rome will be destroyed unless "she" changes her persecuting ways. Nero showed no signs of any such change at the time, but of course Emperor Constantine I did much later sign the Edict of Milan, also known as the Final Edict of Tolerance Toward Christianity, in AD 312.
Verse 10 makes the metaphor painfully obvious. "Terrified at her torment, they will stand far off and cry: ‘Woe! Woe to you, great city, you mighty city of Babylon! In one hour your doom has come!’" In other words, Rome will suffer the fate of Babylon long before her if the policies of Nero continue. Keep in mind that the actual City of Babylon had been in ruins for centuries. It was already an archeological site rather than a current city, hence its use as a byword for just any downfall of a city.
Quod Erat Demonstrandum.