You are correct that the New Testament honors women in a way that was uncommon in the ancient Greco-Roman world. In his book, How Christianity Changed the World, Alvin Schmidt notes that in ancient Greece, women had the social status of slaves. They were not allowed to speak in public, and girls were not allowed to attend school. Women were considered inferior to men, and poets even equated them with evil.
The Romans didn’t treat women any better. They considered a wife to be the property of her husband and granted him complete control over her and everything she owned.
In contrast, Jesus treated women with respect, and two of His closest friends were Mary and Martha. Rather than discouraging women from learning, Jesus encouraged Mary to sit at His feet and listen to His teaching (Luke 10:38–42). He also violated cultural norms when He started a conversation with a Samaritan woman in public. Likewise, the apostle Paul commanded husbands to love their wives “just as Christ loved the church and gave himself up for her” (Eph. 5:25)—a radical idea in the ancient world.
Certainly, the value God places on women in the New Testament seems inconsistent with the Old Testament practice of polygamy. It also seems inconsistent with Genesis 1 and 2, where God creates male and female in His image and the two become one flesh (Gen. 2:24), intended to reflect Trinitarian life and love.
Some believe polygamy is the result of the curse God placed on the woman after the Fall: “Your desire will be for your husband, and he will rule over you” (Gen. 3:16). Sin perverted the relationship between men and women, so it’s not surprising that men begin to take multiple wives and treat those wives as property.
Jesus, after His resurrection, appeared first to women, perhaps symbolizing a reverse of the curse. After the resurrection, polygamy is not mentioned in the Bible, and the one-flesh union is revealed to have even more significance. As Paul notes in Ephesians 5:31–32, it signifies a “profound mystery”: Christ’s relationship to the church.
Scripture always depicts polygamy as causing problems. It seems to be something God temporarily permitted, but (like divorce) only because of the hardness of men’s hearts (see Matt. 19:8).