Does it matter if a Christian marries an unbeliever? Yes, it actually matters more than many Christians realize, particularly if they are not well-acquainted with God’s Word.

Many pastors and elders serving God’s people around the world know by experience that many Christians that willingly marry an unbeliever later fall away from Christ. At worst, when a professed Christian knowingly marries an unbeliever, it expresses unbelief in the Gospel. At best, it reveals a very low view of God and lack of understanding about the Christian life. Either way, there are serious consequences to willfully marrying an unbeliever.

Before we look at God’s Word about this, we need to acknowledge a few things. First, only God knows the heart. Secondly, sometimes a person may believe they are marrying a Christian only to find out later their spouse is no true believer at all. It happens.

Why does it matter that a Christian only marry another believer? Let’s begin with foundational truths and illustrations from the Old Testament. In part two, we will look at the New Testament.

Mixed marriages (a believer with an unbeliever) cannot fulfill God’s purpose for mankind in creation or God’s purpose for marriage.

Genesis 1 teaches us the purpose of God’s creation of mankind. Being made in God’s image, man and woman was to serve God together by ruling over the earth that God had created. They were to continue that great work through children born to them through their marriage relationship.[1] Bearing children was not merely for the purpose of populating the earth or building families; the purpose was to raise up children to serve God in His image.

“She is your companion and your wife by covenant. Did he (God) not make them one, with a portion of the Spirit in their union? And what was God seeking? Godly offspring” (Malachi 2:14-15)[2]

Genesis 2 teaches how intimate this relationship was meant to be between a husband and a wife. They were to perceive the other as an extension of themselves; they were “one flesh”, unified in body by the sexual relationship and in spirit by virtue of their marriage union.[3] Marriage is a covenant between a man and woman before God that He takes very seriously, so much so that God hates divorce.[4]

If a Christian intentionally marries an unbeliever, he/she is despising God’s purpose for mankind, despising God’s purpose for marriage. How can a Christian knowingly marry an unbeliever when they  know that they cannot serving God with them? The unbeliever does not share their understanding of life, marriage, raising children to the know the Lord, etc. Why enter such a serious covenant so callous to these realities?  

Mixed marriages present a serious obstacle to maintaining faith in God.

One of the most important of God’s commands to Israel repeated all throughout the Old Testament era was for Israel to marry only followers of Jehovah. God warned Israel time and time again of the extreme danger of mixed marriages. God prohibited Israel from mixed marriages, warning them that they lead to  falling away from God, into idolatry and unbelief, requiring His judgement.[5]

If we know how much God spoke against mixed marriage all throughout Israel’s history, why would we still think that marriage to an unbeliever is ok, at least in our own case? Shouldn’t the fear of doing something God hates, and thus requiring His chastening, turn us away from considering it? If we know that God’s will is for us to marry another believer, shouldn’t our love for God and fear of Him close the door on this possibility in our minds?

I can think of many reasons why a person might wrongly consider marrying an unbeliever: we allow ourselves to become emotionally attached and fall in love with an unbeliever; lust; deceiving ourselves into thinking that we can make it work or that we will somehow lead them to Christ; or maybe the
“pool” of Christian candidates around us is small and we deceive ourselves with “God understands.”    

“Trust in the LORD with all your heart, and do not lean on your own understanding…Be not wise in your own eyes; fear the LORD, and turn away from evil…” (Proverbs 3:5, 7).

Mixed marriages proved to be a key reason for Israel’s departure from faith in the LORD

The false prophet Balaam was prohibited by the LORD from cursing His people. Balaam knew, however, that if pagan King Balak could encourage his Midianites to intermarry with the Israelites, and thus encourage them into idolatry away from the LORD and His law, Jehovah would judge Israel. Balaam was successful in persuading the Midianites to do this very thing. Israel took the bait, broke God’s law and descended into idolatry, resulting in severe judgment from God.[6]

The book of Judges reveals to us how Israel failed to keep God’s prohibition of mixed marriage and provides us with the sad account of how it resulted in Israel’s failure to possess the Promised Land.[7]

King Solomon–given the spiritual gift of wisdom above all men, the son of David, endowed with incredible wealth and power, builder of the temple of the LORD in Jerusalem and writer of Proverbs, Ecclesiastes, and Song of Solomon–fell away from God in into idolatry. How?!? He had many foreign unbelieving wives. The Scriptures tell us that they stole his heart. Solomon wanted to please them, so he compromised his faith.[8]

The exiles, returning to Palestine after the great captivity, quickly rekindled their former sin of marriage to unbelieving foreigners. The prophets Ezra and Nehemiah spoke out against this and led the people to renew their covenant with the LORD. Mixed marriages were referred to as “faithlessness” and “breaking faith with God”.[9] The people understood that the “fierce wrath of God” was upon them because of this sin.[10]

These Old Testament illustrations are so many and so profound that God’s people today should be fearful of knowingly entering into a marriage covenant with someone who does not share their faith in Jesus Christ. To arrogantly marry an unbeliever anyway reveals a heart of pride which believes God’s wisdom is foolishness and the fulfilment of one’s own desires wisdom. The saying is true that the most dangerous form or deceit is self-deceit.

In part two, we will look at what the New Testament has to say about this important question.

[1] Genesis 1:26-30

[2] All Scripture quotations are from the ESV unless otherwise noted.

[3] Genesis 2:18-25

[4] Malachi 2:14-16

[5] Deuteronomy 7:1-4

[6] Numbers 25, 31

[7] Judges 3:1-6

[8] 1 Kings 11:1-8

[9] Ezra 9:1-5, 13-14; 10:2, 10-11

[10] Ezra 10:14