The Babylonian army descended upon Judah in the sixth century BC, destroying the city of Jerusalem and the temple of God in 586. The people had been consistently warned this would happen, but they were confident it would not be so, even though the Northern Kingdom Israel had suffered a similar fate some 150 years earlier. The prophets warned Judah repeatedly that their idolatry—looking to things other than God for their safety, satisfaction, and fulfillment—would end badly. And because the vertical relationship between God and the people was broken by idolatry, the horizontal relationship between people also suffered greatly.
The prophets also warned the people about this. Their social injustice—exploitation of the poor, the orphan, the widow, the stranger—would also bring about God’s judgment. But why were God’s people so confident that judgment would not befall them? In a word (or two): religious ritualism. They were convinced that simply going through the motions of worship was sufficient to keep God happy and secure his blessing. Idolatry, social injustice, and religious ritualism.
Malachi, whose name means “My Messenger,” confronted God’s people about these same three sins. Even though he preached to Judah many, many years after Jeremiah, the people of God continued to sin against him in the exact same way. Despite having experienced the horrors of exile and having seen God’s faithfulness in returning them to their land some years later, the people go back to sinning in the same way as their forefathers.
In Malachi 2:11 we read, “Judah has acted treacherously, and a detestable thing has been done in Israel and in Jerusalem. For Judah has profaned the Lord’s sanctuary, which He loves, and has married the daughter of a foreign god.” God’s people were warned against marrying those who worship foreign gods because the result would be their own idolatry. This happened to Solomon (1 Kings 11), to Israel in the wilderness (Numbers 25), and now we see it again. Marriage to those who worshiped other gods is particularly pernicious because it inevitably leads to the people themselves worshiping other gods.
In addition to idolatry, Malachi castigated the people for social injustice. In 2:17 we read, "You have wearied the Lord with your words. Yet you ask, ‘How have we wearied Him?’ When you say, ‘Everyone who does what is evil is good in the Lord’s sight, and He is pleased with them,’ or ‘Where is the God of justice?"
In response to this attitude that God is unconcerned with justice, he states that he will judge their own injustice: "I will come to you in judgment, and I will be ready to witness against sorcerers and adulterers; against those who swear falsely; against those who oppress the widow and the fatherless, and cheat the wage earner; and against those who deny justice to the foreigner. They do not fear Me,’ says the Lord of Hosts.”
As before, the broken vertical relationship (idolatry) has led to a broken horizontal relationship (social injustice). And God is imminently concerned that his people treat others well because his people are to be a light to other nations. Of course this includes proper worship (the vertical relationship), but it’s also highlighted in how His people treat the least of these around Him.
And, just as before, the people believed they had nothing to fear because of their religious ritualism. They thought all that was needed to earn God’s favor and avoid his wrath was to go through the motions of a relationship with Him. The Lord says through Malachi, “When you present a blind animal for sacrifice, is it not wrong? And when you present a lame or sick animal, is it not wrong? . . . You bring stolen, lame, or sick animals. You bring this as an offering! Am I to accept that from your hands?” (Malachi 1:8,13). See, the priests thought that simply going through the motions of religious sacrifice would be sufficient to please Yahweh and avert his wrath, but such was not the case. They displayed a fundamental misunderstanding of what it means to be in relationship with God and love him fully.
God’s people have been committing this trifecta of sins for quite a long time. It’s these sins that the prophets of the Old Testament preached against before the exile and again after it. And it is these sins for which Jesus in the New Testament castigated the Pharisees. They misunderstood what it meant to have a right relationship with God. As a result, they trusted in their adherence to religious acts to secure a relationship with God, all the while despising him by ignoring the “the more important matters of the law—justice, mercy, and faith” (Matthew 23:23).
And here’s the thing: we continue to commit these same sins today. The thinking so often goes that we can place our hope in our job, bank account, or any number of other things, just as long as we go to church on Sunday, give our tithe, and maybe read the Bible here and there if we need an emotional boost. And don’t worry about the poor, the orphan, the widow, the immigrant, or the refugee because, after all, we went to church this Sunday and we even gave a tithe. Yet this type of thinking is startlingly dangerous—it led to exile in the Old Testament and the rejection of Christ in the New Testament. Let us learn from God’s words through Malachi and seek out a true relationship with God characterized by Jesus’s words in Matthew 22:37–38: “Love the Lord your God with all your heart, with all your soul, and with all your mind. This is the greatest and most important command. The second is like it: Love your neighbor as yourself. All the Law and the Prophets depend on these two commands.”
 This terminology comes from J. Scott Duvall and J. Daniel Hays, Grasping God’s Word: A Hands-On Approach to Reading, Interpreting, and Applying the Bible, 3rd ed. (Grand Rapids, MI: Zondervan, 2012).