Does the Bible command women to cover their breasts? Tribal women in Africa, South America and Papua New Guinea have gone around with bare breasts for countless generations. When Christian missionaries arrived they convinced the women to cover their breasts. What arguments did they use to achieve this? I see nothing in the Bible about God commanding women to cover their breasts.
No, there are no explicit instructions in the Bible to not have bare breasts. Biblical references to modesty are interpreted differently given a particular time and place -- similarly with interpretations of 'nakedness.' There is no explicit verse covering the topic, Christians must infer instructions of modesty on their own. This has been accomplished in a wide variety of ways throughout history. Contemporary women's clothing would be have been considered horrifyingly indecent centuries ago, but they are commonly worn by Christians today.

The only specific article of clothing that a small minority of Christians adhere to is St. Paul's instruction for women to cover their heads (1 Corinthians 11:1-16). Many contemporary Christians interpret that instruction to be specific to the congregation he was speaking to due to the context of their time and place (same with the references to gold, pearls, and remaining silent).