A problem to mention, but which would take us too far afield, is the reference to the choice of Jacob as having been God's, when the Torah portrays it as Isaac's. If God had really already settled on Jacob as the recipient of the important blessings, we ought to wonder why the Torah saw fit to record a sham competition. Along similar lines, we could wonder why Rebecca did not simply tell Isaac of the pre-birth prophecies regarding the twins.
Those questions, aside from affecting our understanding of that piece of Torah, touch on important general religious concerns, such as the interplay between freewill and Divine intervention, but are less directly related to the haftarah itself.
Jacob over Esau: The Larger Picture
Turning our focus there, we realize that Malachi's real complaint focuses on the Jews - particularly the priests - mistreating the Temple service. Instead of bringing appropriate offerings, they are bringing stolen and blemished animals, acting towards God in not nearly the way they would treat a human father or king. The mention of Jacob and Esau turns out to be a minor point in the broader complaint, an instantiation of why the Jews' treatment of God is so wrong.
The explanation lies in metaphor and its value. Malachi opens the piece by declaring it a "massa," which Rashi translates as a load carried from somewhere else. He adds that the Sages deduced from this that all the prophets were at Sinai, where they received their personal messages. Using the word here seems to emphasize how inherent Malachi's message is in the Sinaitic revelation, that the choice of Jacob over Esau reflects something crucial in our relationship with God.
The word "relationship" is strange when it comes to God, at least for philosophically-inclined Jews, but I use it because the metaphor of family holds the key to Malachi’s complaint. As the prophet disparages the Jews' treatment of God, he sees it as an example of a generally distressing phenomenon, our reserving our cruelest comments, our most outrageous behavior, for the confines of family.
This is how the Jews of Malachi's time treated God. Strangers came with reverence, as did pagans, who only respected God as one among many. In contrast, the Jews were bringing lame, stolen, and otherwise unfit animals. It is a common paradox: our comfort with family (and, in this case, God) brings out the worst in us.
The stress on Esau as part of the family also suggests that the rejected brother could still rejoin, could still get back into God's good graces, even into the nation. Since that has not yet happened, the haftarah leaves us wondering (even hoping) for that time.
The family metaphor explains two further aspects of the haftarah, the Jews' not understanding their crime, and the focus on the tribe of Levi. Malachi notes that the Jews offer these various improper sacrifices and feel "there is no evil," another too-common element in family squabbles. We can, unfortunately, speak to parents, children, spouses, and siblings with a bite and a disdain that would horrify us in public. Within the family, we dismiss its seriousness.
The responsibility for changing that family dynamic lies with each member of the clan, but even more so with the leaders, whose job is to teach, remind, convince and/or coerce the rest of the gang to behave appropriately and properly. Translated to Temple service, that means that the priests - who in Malachi's time were apparently accepting and offering the improper sacrifices - deserved condemnation for their failures, and were being told to improve their own actions, to serve as a model for others, and to train the Jews as to the proper way to serve God.
A family dynamic can be changed, and so can our dynamic with God. From the contempt of familiarity, we can move to expressing always the love and connection we feel for those closest to us, and, we should hope, for God.
Phrases in Maimonides' Writings
Since Maimonides quotes several phrases from this haftarah, I thought it might be interesting to see the uses to which he puts them.
Chapter 1, verse 7: The prophet says that "the Table of God is denigrated," which Maimonides in Guide to the Perplexed III, 46 sees as the underlying reason for the laws about how to treat an animal sacrifice. For him, the requirement to wash the various parts of the animal and the prohibitions against certain people eating them, stem from the need to treat the sacrifice as the bread of a king. Just as the family metaphor was useful in its context, "food" as a metaphor guides how treat God’s "Table."
Chapter 2, verse 3: God warns, "and I will spread dung on your faces, the dung of your festivals," which Maimonides cites twice in the context of eating improperly. First, in Laws of Character Traits 5:1, Maimonides cites the verse to characterize those who chase food for the pure pleasure of eating, meaning that he understood Malachi to be complaining about the Jews' using the holidays as an excuse to eat meat, not as a religious experience of closeness to God. He makes the same point in Laws of Holidays, 6:18, when he says that those who eat on the holidays without caring for the poor or needy turn days meant for religious growth into a purely physical (and therefore negative) experience.
Chapter 2, verse 6: The verse refers to the priest walking "in peace and straightness" which the Talmud, cited by Maimonides in Avot 1:12, applies to Aaron, seeing him, in contrast to Moses, as a source of peace and unity among the people.
Chapter 2, verse 7: The verse announces that "the lips of a priest will guard wisdom, and others will seek wisdom from his mouth, for he is an angel of God." Maimonides takes that both as a proof that it is appropriate to call a Torah scholar an angel of God (Avot 5:13, which allowed him to read some Biblical references to angels as actually meaning people) and, based on the Talmud, as a warning that we should only study with teachers who rank well both in knowledge and character - if the teacher is an angel of God, we should accept Torah, but if not, not.
In summary, then, the haftarah shows Malachi's use of the metaphor of family (and of food) to protest the Jews' treating God and the Temple too familiarly, allowing themselves to insult God egregiously, and then deny having done wrong.