I think this is one example of where biblical theology is really important in understanding a Bible passage.
Did you notice that in the passage, the idea of the ‘covenant’ crops up twice – once in verse 10 (the ‘covenant of our fathers’) and once in verse 14, referring to the marriage covenant between a man and a woman? A covenant is basically a special solemn relationship involving obligations between two parties. This passage in Malachi relates together the covenant between God and Israel (the ‘covenant of our fathers’) with the covenant between a man and a woman – the marriage covenant.
This is very important, because the passage is referring back to the covenants which God made with the ancestors of Israel – with Abraham, Isaac and Jacob. You can read about the covenants between God and Abraham in Genesis 15 and 17, and these covenants culminate in an oath from God in Genesis 22:17-18:
I will surely bless you, and I will surely multiply your offspring as the stars of heaven and as the sand that is on the seashore. And your offspring shall possess the gate of his enemies, and in your offspring shall all the nations of the earth be blessed, because you have obeyed my voice.”
Do you notice the word ‘offspring’? It’s the same word as you find in Malachi 2:15:
Malachi 2:15 Has not the LORD made them one? In flesh and spirit they are his. And why one? Because he was seeking godly offspring. So guard yourself in your spirit, and do not break faith with the wife of your youth.
Literally, the word ‘offspring’ means ‘seed’. And to be more precise, the phrase in Malachi 2:15 should be translated ‘Because he was seeking offspring [or seed] of God’.
What’s going on here? In Genesis, God promises that Abraham will be a very special person. He will be the father of a great ‘seed’. That ‘seed’ will be victorious over his enemies, and will be the source of blessing for all the other nations of the earth. So a very important part of the covenant between God and Abraham is that there will be an ‘seed’ who will be the source of blessing for the whole world. This is God’s purpose for Abraham and his descendents, the nations of Israel. Clearly, this ‘seed’ wil lbe produced by procreation between husbands and wives in Israel.
At the time of Malachi, we can see that God still has this purpose in mind for Israel. He is still seeking ‘seed’ to be the source of blessing for the world. The Israelites should be faithful to their covenant with God, which in turn will mean that they will be faithful to each other in their own marriage covenants (i.e. not divorcing), will keep themselves distinct as the nation of Israel (i.e. not marrying foreigners), and produce ‘offspring’ that will be the source of God’s blessing for the world.
But the problem in Malachi is, they aren’t being faithful, either to their covenant with God (in remaining distinct from the nations), or their covenant with their own wives (in staying faithful and not divorcing them). You can hear the exasperation in Malachi’s voice – how are God’s purposes going to be achieved when the covenant itself, and so the ‘seed’ of God, is still in jeopardy?
The ultimate answer is found in Jesus, the true seed of Abraham. Jesus the Israelite was faithful to God’s covenant, and he is the seed whom God was seeking. In Galatians 3, we read:
Galatians 3:16 The promises were spoken to Abraham and to his seed [or, offspring]. The Scripture does not say “and to seeds,” meaning many people, but “and to your seed,” meaning one person, who is Christ.
And through Jesus, we share in that promise:
Galatians 3:29 If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise.
That’s why Malachi is so concerned about the ‘seed’ at this point in God’s plan – because Jesus, the true seed, had not yet come, and the whole covenant seemed in jeopardy by Israel’s faithlessness in marriage, at the very point which should be producing the seed of God.
Now what does that mean for us, now that the seed has come? Well, even though we’re not Israelites and we don’t have to produce any ‘seed’ to bless the world with, faithlessness in marriage is still wrong! We should remain committed to our marriage covenants, because that is God’s character – he is faithful to his covenants, so we should be faithful to ours. And although I don’t think it’s the main point of the passage in Malachi, it’s still an important point to say that a strong commitment in marriage will be hugely beneficial for the children of that marriage – really the most important thing you can do for your kids (or your future kids!) is to be fully and wholeheartedly committed to your spouse (or your future spouse).
But does that mean that children from broken families, or children from mixed marriages between believers and unbelievers, are somehow less ‘godly’ or ‘legit’ or ‘impure’? Not at all! Paul addresses this issue in 1 Corinthians 7:13-15:
1 Corinthians 7:13-15 13 If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. 14 For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband. Otherwise your children would be unclean, but as it is, they are holy. 15 But if the unbelieving partner separates, let it be so. In such cases the brother or sister is not enslaved. God has called you to peace.
The point that Paul makes is that now, because Christ has fulfilled the covenant between God and Israel, the children of Christians are ‘holy’ (which I take it here means something like ‘pure’ or ‘legitimate’, not necessarily ‘saved’) even if they are married to an unbeliever, or even if their unbelieving spouse leaves them.
This is actually great news for kids from broken or ‘mixed’ marriages – even if one or both of your parents have done stupid things in their marriage and things are pretty bad, this doesn’t mean God has abandoned you to your fate and you’re doomed forever with the sins of your parents.