Zaatari therefore concludes that this verse is saying that God's nature doesn't change and since he believes the incarnation presupposes a nature change in the being of God he believes this refutes New Testament Christology.
The Same Malachi Actually Predicts the Incarnation of God!
If that wasn't bad enough Malachi actually affirms God's incarnation through the awaited one (Jesus Christ) further demonstrating that 3:6 isn't referring to God not changing with respect to an incarnation. In chapter 3 v. 1 it says: "Behold, I send my messenger, and he will prepare the way before me. And the Lord whom you seek will suddenly come to his temple; and the messenger of the covenant in whom you delight, behold, he is coming, says the LORD of hosts." With respect to a future where all the Gentile nations will worship God and where a remnant of Israelites will be saved, God says that a messenger will prepare a way for Him (John the Baptist in Luke 3:1-6 preparing the way for Christ in John 1:29-34.) The text then affirms that God will come to His temple which entails God lowering Himself which is what Christ did (Matthew 21:12) as well as God being the one who comes down to "purify the sons of Levi and refine them like gold and silver" (v. 3). This is incarnation language.
Hence, even in Malachi itself there is attestation to God literally coming to His people after a messenger prepares the way, going to the temple and purifying/refining the sons of Levi. Therefore, this book in no way supports the idea that if God entered into His creation it would violate Him as not being a God who doesn't change.
Non-Christian Jewish Rabbi's, expositors and commentators have likewise noted that the one who will come to His temple, and who is God, is in all actuality the Messiah.
The First Book of the Bible Teaches that it is in God's Nature to Become a Man!
Contrary to Muslim misuse of Malachi 3:6 we have seen that this verse emphasises God not changing with respect to judgment and mercy as opposed to a denial of an incarnation. We have also seen that Malachi itself strongly attests to an incarnation of God. We also saw that God coming to His temple in the form of Messiah is not just a Christian inference but that Jewish expositors and commentators also affirmed that God would appear as the Messiah. And finally, we have seen that such a concept is not unknown to Scripture. In fact, the very first book of the Old Testament has God taking the form of a man and yet remaining the unchanging God.