We need to cover a few definitions before beginning this short Bible study. The definition of polygamy is one man married to more than one woman, or one woman married to more than one man. Strictly speaking, the practice common in the Old Testament of one man having multiple wives at one time is known as polygyny ('poly' meaning 'more than one' and 'gyny' or 'gune' in the Greek meaning 'woman'). Polyandry is the situation where one woman is married to more than one man.
Monogamy, as most people are aware, occurs when a person has only one mate their entire life. In serial monogamy, people still are only married to one person at a time (versus polygamy where one person is married to many at one time) but they marry more than once in their lifetime (e.g. a person divorces one mate then marries another one).
An important fact to remember regarding polygamy is that it has fundamentally always been something that only rich and better off men could take advantage of, since maintaining more than one wife and set of children in separate households is financially expensive.
The Old Testament is clear about its view of multiple wives among its human kings. What few people realize, however, is no passage exists that forbids polygamy among Israel’s tribes. Although God himself ruled Israel when they came out of Egypt, he knew there would likely be a time when they would want a human king over them. Although He warned any future Israelite king that they should not possess MANY wives, God did not command that they must have one and only one.
14 'After you have taken possession of the land that the LORD your God is going to give you and have settled there, then you will decide you need a king like all the nations around you . . . 17 The king is not to have MANY wives . . .' (Deuteronomy 17:14, 17)
By the time of Jesus' ministry and the early church, the general practice of polygamy had largely died out in the Roman Empire. Although the Romans themselves did not practice it, they did divorce and remarry when they wanted to change spouses (serial monogamy). Exceptions existed, such as Herod the Great (who was an Edomite and not a Jew), who was a polygamist. Although the New Testament does not directly address this marital arrangement, the fact that it says almost nothing about the practice points to its decline, even elimination, among the people of God.
Apostle Paul's teachings
The Jewish writings known as the Mishnah and Talmud sanctioned polygamy. There are several Scriptural-related passages on marriage in the writings of Paul, however, that do strongly infer that it was (and is) not acceptable among Christians. Paul, for example, instructed his best friend and fellow-evangelist Timothy that one of the traits to look for in a good church leader was that he was "the husband of one wife" (1Timothy 3:2, see also verse 12). He wrote this admonition to Titus as well, who was preaching the gospel and helping believers on the Island of Crete (Titus 1:5 - 6). The church in Corinth was told one way to help avoid sexual immorality was to ensure that each person had one mate (1Corinthians 7:2).
Writing about the decline of this type of relationship in the world at large, James Q. Wilson stated the following in his book "The Moral Sense."
"The ground was prepared for the growth of individualism and universalism by the dramatic changes that occurred in family life during some thousand years, stretching from the end of the Roman Empire to the Renaissance. In this time, 'monogamous marriages triumphed over polygamy and male divorce power, and gradually shifted its focus away from parental and kinship concerns [i.e., arranged marriages, etc.] . . ." (Page 205)
What should Christians do in regard to polygamy? They should submit to the laws in the land they live in so long as they do not conflict with what the Bible teaches (see Romans 13). A large percentage of countries in the 21st century have laws against such marital arrangements, with the exception of countries governed or influenced by Islam. For these and other reasons, modern-day believers should reject this ancient practice.