The Bible does not explicitly state why God allowed polygamy in the Old Testament. (AT). However, based on what Scripture teaches about marriage and the gospel, we are certain that that polygamy is not God’s purpose for humanity.
polygamy and marriage
The term “polygamy” implies that a person has more than one marriage commitment or that a man has many wives (Deut 17:17; Judges 8:30; 1 Kings 11:1-8). Both cases go against the commandment that God established for the family. According to Genesis 1:27 and 2:24, the model of marriage according to the will of God is a monogamous relationship between a man and a woman. Jesus himself quotes these passages in matters of divorce to reiterate the pattern established by God “from the beginning” (Mt 19:4-6). Particularly noteworthy is the constant use of the singular: “Por tanto el men (singular) will leave his father and mother and join his woman (singular), and they will be one flesh” (Gen 2:24, Mt 19:5, emphasis added).
Yes ok in the Old Testament many characters practiced polygamy, in the Scriptures this practice is never supported. Although polygamy was not an impediment for God to use certain characters, all those who practiced it suffered pain, reprisals, and spiritual decline at some point in their lives (Gen 21:11; Judges 9:5,18; 1 Kings 11: 1-8; Neh 13:26).
Therefore, Paul with knowledge of the Scriptures and wisdom indicated that every leader of the church should be a “husband of just one woman” (1 Tim 3:2; 3:12; Titus 1:6, emphasis added). In this same sense, “because of immoralities,” Paul instructs believers to “each have his own wife, and each have her own husband” (1 Cor 7:2). Through passages like these, Christian thinker Norman L. Geisler noted that Paul “emphatically excludes polygamy” from the Christian life.
Polygamy and the Gospel
One of the most important things when considering the issue of polygamy is that marriage has a purpose to point to the gospel. You may wonder how. In Ephesians 5:31, Paul quotes the first few passages of the Bible to discuss roles in marriage and then reveals that he is speaking “with reference to Christ and the church.” In other words, the original marriage between a man (singular) and a woman (singular) foreshadows the heavenly marriage between Christ and his “wife,” the Church (Rev 19:7, 21:2; cf. Is 54:5; 62:4-5). Therefore, the deviation from the original pattern of marriage results in the distortion of the truth that it communicates of the gospel.
conclusion
Although God allowed polygamy in the OT, we know that monogamous marriage is the established family model for humanity. Above all, because polygamy is a deviation from the original pattern of marriage; and this ultimately reflects a distortion of the gospel.