In chapter 1 we heard about the Israelites (and us) giving shoddy gifts to God. But if God was giving the things in the first place, why be niggardly about giving some back to him? It was because the Israelites didn't believe God was the source of the things they had. They believed they were responsible for their own good fortune.
Ask yourself: if you had to say, fairly, how much of the 'good stuff' in your life (family, kids, house, car, job (and how well you're doing in your job) etc) is down to God, and how much is down to you, what would you say? Fifty-fifty? Sixty-forty? Seventy-thirty? Which way?
Is it fair to say that, whilst God is there for the 'big decisions' and 'special request' prayers, he pretty much leaves most of the day-to-day stuff to us? Don't get me wrong: he's still the head honcho - Mr Big if you like - but we take care of the ordinary stuff, and to be honest we do a pretty good job. We're doing quite well thank you.
What a lot of nonsense. Every good thing comes from the Lord. So God says,"Freely you have received, freely give".
But once a person begins to attribute their well-being to their own efforts, they begin to worry about their 'stuff'. If they trust in themselves they are no longer secure, because they are fallible. They begin to hoard. They become selfish towards others in need, who they may be in a position to help, but don't because, well, if I give to that person from my stuff, I'll have less stuff: oh no!
This is the situation at the beginning of Malachi 2. The people have forgotten that God is the source of their blessings, so begin to 'qualify' their love for him. As verse 2 says, "You have not set your heart to honour me."
Sadly, it is usually the case that the more money a person has, the less generous they become. God's only recourse for a people that have hardened their hearts and begun to doubt the source of their blessings is to take those blessings away:
 "And now this admonition is for you, O priests. If you do not listen, and if you do not set your heart to honor my name," says the LORD Almighty, "I will send a curse upon you, and I will curse your blessings. Yes, I have already cursed them, because you have not set your heart to honor me.
But this is not blind anger, rather a shock tactic to awaken his people to the reality of the situation. It is because of God's covenant with his people that they are even alive, that their nation has survived when so many others have disappeared from the face of the earth. These are the days of the Babylonion empire, remember:
 And you will know that I have sent you this admonition so that my covenant with Levi may continue," says the LORD Almighty.  "My covenant was with him, a covenant of life and peace, and I gave them to him;
But he reminds the priests that the covenant was not meant to be one-sided. The priesthood was founded to be a guiding light to keep the people holy:
[5+] this called for reverence and he revered me and stood in awe of my name. True instruction was in his mouth and nothing false was found on his lips. He walked with me in peace and uprightness, and turned many from sin.
 "For the lips of a priest ought to preserve knowledge, and from his mouth men should seek instruction--because he is the messenger of the LORD Almighty.
That was how it was supposed to be.
 But you have turned from the way and by your teaching have caused many to stumble; you have violated the covenant with Levi," says the LORD Almighty. "So I have caused you to be despised and humiliated before all the people, because you have not followed my ways but have shown partiality in matters of the law."
This is us. Christians. We are the priesthood, we are the ones charged with proclaiming God's truth in the world. We may talk the talk, but we do not walk the walk - we have watered down the truth by our actions or lack of them. Our lives do not reflect the belief that every good thing comes from the Lord. We do not act like aliens in a foreign land, travellers en route to heaven. We have settled in this land and made it our own.
And we are despised and humiliated before all the people. Allah has more respect in this land than Jehovah. Do we care? Enough to do something about it? "True instruction was in his mouth and nothing false was found on his lips." Can we be like Levi?
The second half of this chapter is a rebuke for the people, rather than the priests. They were divorcing their wives and marrying women from other nations who worshipped other gods. God compares their individual unfaithfulness to the unfaithfulness of the nation:
 Judah has broken faith. A detestable thing has been committed in Israel and in Jerusalem: Judah has desecrated the sanctuary the LORD loves, by marrying the daughter of a foreign god. As for the man who does this, whoever he may be, may the LORD cut him off from the tents of Jacob--even though he brings offerings to the LORD Almighty.
 Another thing you do: You flood the LORD'S altar with tears. You weep and wail because he no longer pays attention to your offerings or accepts them with pleasure from your hands. You ask, "Why?" It is because the LORD is acting as the witness between you and the wife of your youth, because you have broken faith with her, though she is your partner, the wife of your marriage covenant.
 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.
 "I hate divorce," says the LORD God of Israel, "and I hate a man's covering himself with violence as well as with his garment," says the LORD Almighty. So guard yourself in your spirit, and do not break faith.
The people have been unfaithful to their Jewish wives in the same way the priests have been unfaithful to Jehovah. The Lord will not accept their offerings because He is acting as the witness, reminding them of their youth, and of the covenant they entered into with the Lord of Hosts. They may have forgotten their vows, but He has not.
This isn't a negative book, and despite appearance, this isn't a negative sermon. At the start of Malachi, God used his hatred of Edom to highlight his love of Israel. In chapter two He is opening the people's eyes to the truth of the situation. Now, as then, a person can only repent when he realises how far he has fallen from the place God has prepared for him. God is reminding the Israelites of who they are and who they were in order to urge them towards repentance: that they may love him as he loves them.
This chapter is a beacon of hope, pointing to the climactic finale of chapters 3 and 4, when God says the day of his coming is near, and you will trample down the wicked. God's people are not 'the wicked', but they have forgotten how to be God's people, and are not ready for the day of the Lord's coming.
Malachi is the messenger who will prepare the people: are you prepared to be prepared?