Answer:
In the allegory of Genesis, the pattern was clearly set as one man-one woman. Even in viewing it as the extended comparison of Christ as the “one man” and His church as the “one woman” it is still “wife” in the singular.
In Deut. 17:17, God warned against the practice of polygamy among future kings of Israel: “Neither shall he multiply wives for himself, lest his heart turn away.” Indeed, years later when King Solomon took many wives, he faced such consequences. (see 1 Kings 9:6-9; 11:1-11).
The principle of one man and one woman is taught in Matt. 19 and in Paul’s letter to the Ephesians (5:21-23). In 1 Tim. 3:2-12 and Titus 1:6 we learn the qualifications for elders and deacons in a local church included the bishop have only one wife. In the New Testament church, polygamy was expressly forbidden. God intended and intends for marriage to be between two.
However, if this is God’s standard, why did he tolerate the practice of having more than one spouse at a time, especially among His people?
Just because God, for example, tolerated Jacob to take two wives and two concubines, it does not mean that God preferred the practice. Nor does it mean there wasn’t folly in it. In fact, jealousy and bickering went on for years in Jacob’s household due to his having more than one wife. Besides Solomon’s life, another example of the failures of polygamy is found in 1 Sam. 1 that tells of Elkanah and his two wives, Hannah and Peninnah between whom jealousy and bitterness reigned. Does this not show that God’s way is best?
In a like manner God permitted divorce during Moses’ time (see Deut. 24:1-4; Matt. 19:8) even though divorce is also expressly not His will. Divorce was permitted due to the hardness and stubbornness of peoples’ hearts and not because God willed it so. God never intended marriage be between more than two, nor for divorce to take place.