1. Judah has been unfaithful (10-12)

Not only had God created the Israelites, he also established a covenant with them. God was their Father which meant they had a special, covenant bond with each other. But the Israelites were unfaithful to each other. Their unfaithfulness to God and each other was expressed by intermarrying with idol-worshiping women. Malachi prayed that those who intermarried would be removed from the covenant community.

2. You belong to God (13-16)

The people flooded the altar with their tears because God no longer accepted their offerings. They asked, "Why?" The answer was simple - men divorced the wives of their youth to remarry. The LORD likened it to committing violence against one's wife. God hates divorce. Marriage is a physical and spiritual union established by God for the purpose of producing Godly offspring. Thus, divorce is an affront to God and his covenant.