Polygamy and Christanity

While Judaism did not legally forbid polygamy, its use was strongly discouraged since the Babylonian Exile. Many of the later OT books assume universal monogamy. By the time of Christ, polygamy was rarely practiced among Jews, and was tolerated only because no one had the legal authority to forbid it. [See: <http://www.jewishencyclopedia.com/articles/10949-monogamy>]

Christ's injunctions against divorce and remarriage would lose all their weight if they could be so easily circumvented by taking multiple wives. The sense of these teachings is that marrying another spouse is an act of adultery against the first spouse. In fact, the crime of divorce and remarriage was always considered bigamia in Christian usage.

In John 5:17-18, Jesus tells a woman: "Though hast said well, I have no husband, for thou hast had five husbands..."  The implication is that having multiple husbands, even in series, is incompatible with marital fidelity. Much less could Christ's teaching admit simultaneous plurality of spouses.

See also Matthew 19:29 (Lk 18:29). Brothers, sisters, and children are given in the plural, since you can have many of these. Yet father, mother, and wife are given in the singular, since it is assumed that you can only have one of these at a time.

The fact that none of the surrounding nations practiced perfect monogamy indicates that the Apostles could have received their teaching (1 Tim. 3:2, 12; Titus 1:6) from none but the Master. The Pauline teaching was strictly interpreted in East and West as forbidding any sort of bigamy in clerics; that is to say, they could not have a second wife even after the first died.

The universality of monogamy among early Christians is attested by Bardesanes the Syrian Gnostic (2nd cent.):

"And what shall we say concerning the sect of the Christians? For we who hold those opinions have arisen in multitudes in different climes, in every nation and region, and though many in number, are called by one name. And neither in Parthia do the Christians, Parthians though they are, practise polygamy, nor do those in Media cast their dead to dogs, nor do those in Persia, though they are Persians, marry their daughters, nor among the Bactrians and the Gauls do they form unnatural unions..."

http://www.tertullian.org/fathers/eusebius_pe_06_book6.htm

Christians did not imitate the polygamous and unnatural practices of the nations in which they lived. More fundamentally, they rejected any national custom that allowed what was forbidden by their Teacher. They seemed to form a distinct nation based on their own principles.

Christianity is so sharply distinguished by its purity in marital matters, that no credible account of it could allow the licentiousness implied by polygamy. At any rate, there is no positive evidence of the practice in early Christian churches, even in heretical sects.