Woman Wants to Convert to Christianity because Husband Took Second Wife
19-7-2003 | IslamWeb
Question:
Just now I spoke to a lady from Canada and she divorced her husband 2 years ago. She has 2 sons. The reason for the divorce is her husband had second marriage in Egypt that angered her. Now she wants to convert to Christianity. I want you to stop her by giving good advice. She posed a question "Why did God permission for husband to get married as he likes"? She wants the answer to the question. Please stop her from that by giving good answers from Qur'an and Hadith, I felt it my duty to inform you so that you can answer her better. If Allah wishes, He will stop her from converting.
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
The Muslim should not say: “Why has Allah made this lawful?” He should only ask: “What has Allah made lawful?” This is because the first question implies challenging Allah's ruling. Allah tells us in His Book that the believers have no option as regards His Decrees and Rulings. Allah Says (what means): {It is not for a believer, man or woman, when Allah and His Messenger have decreed a matter that they should have any option in their decision. And whoever disobeys Allah and His Messenger, he has indeed strayed in a plain error.} [Quran 33:36]
Allah has made it lawful for man to marry up to four wives at a time. He Says in the Quran (what means): {Marry women of your choice, two or three, or four.} [Quran 4:3]
However, one cannot marry more than one wife unless he is capable of maintaining them and treating them equally. Allah Says (what means) in this regard: {…but if you fear that you shall not be able to deal justly (with them), then only one…} [Quran 4:3]
The Messenger of Allah told Ghaylaan Ath-Thaqafee when he embraced Islam while he had ten wives and all of them embraced Islam along with him, “Retain only four of them and divorce the rest.” [Ahmad, At-Tirmithi and Ibn Maajah]
There is no doubt that all Commandments and Rulings of Allah are based on wisdom, justice and mankind's interest. Mankind may or may not know this.
The clear logical reason for allowing men to have more than one wife and for not allowing women to have more than one husband at a time is that if women are allowed to have more than one husband at a time, this will cause mix-up of lineage, contention of the husbands and a great corruption. If, for instance, a woman is married to four men at a time, it will be impossible to determine the paternity of the child.
Hence, there is no religion or law that allowed a woman to have more than one husband at a time; though all religions allowed men to marry more than one woman at a time.
Furthermore, no one should assume that the religious traditions of the Jews and the Christians forbid polygamy. They rather allowed it. For instance, the people of the Scripture read in the Old Testament that Prophet Ibraheem (Abraham) 
had two wives, that Prophet Ya'qoob (Jacob) married four women, that Gideon, the son of Joa'sh, had many wives and had seventy sons who were his direct descendants. (Judges 8:30), that Prophet Daawud (David) married many women and the names of seven among his wives were mentioned and that he married many others, and that Prophet Sulayman (Solomon) married 1,000 women, 700 of whom were daughters of kings and 300 were maids.
If the reason for wanting to convert to Christianity is because Islam allows men to marry more than one wife, the Christians also should affirm polygamy because it is available in the book they believe in, or they should at least, concede the fact that polygamy was lawful in the laws of some of the past Prophets and it should not be an object of derision and surprise if it is allowed by Islam.
Whoever casts a keen look at Islam and its rulings, and its establishment upon justice and wisdom, he will realize Allah's favor in preserving this religion, the Quran and the Sunnah.
Christianity on the other hand, is full of contradictions and discrepancies that are enough to prevent any wise person from even thinking of embracing it.
One of its absurdities is the trinity that teaches that God comprises of three beings: the father, the son and the Holy Spirit, and that these three beings are equal in eternal power. The belief further teaches that, though there are three godheads, this does not mean that there are three gods but only one God. It also teaches that trinity is beyond human understanding. This is only one example of the perversion in Christianity's greatest doctrine which is trinity.
We pray that Allah guides this sister and make her stand firm on the true religion and open up her heart for all that is good.
For more benefit on the wisdom for legislating polygyny (or polygamy) in Islam, please refer to Fataawa 86893, 86818, 183395, 91137, and 89278.
Allah knows best.