Thank you so much for this excellent question!  Well, my dear friend, the short answer to your question is that verse 6 underscores God’s immutability in terms of both His righteousness and His grace; He is unchanging in terms of His divine attributes, His perfect will, and His purposes for the restoration and blessing of His people (see also James 1:17; Hebrews 13:8). But how is this truth brought out in the verses you have cited? In Malachi 3:6 we read: “For I am the LORD, I change not; therefore ye sons of Jacob are not consumed.” Now, to really understand the context of this verse, let me expand a bit on the book of Malachi.  Malachi was written over 400 years before Christ, and it constitutes God’s final urging of His people in the Old Testament, so that they might return once again to a true love and worship of their God. By way of background, the nation of Judah had been exiled to Babylon because their hearts had grown cold towards God.  For 70 years they had languished in the land of their oppressors due to the infidelity of the hearts of the people. By the time of Malachi, Judah had graciously been allowed by God to return to Israel from exile, and the children of Israel had rebuilt the walls of Jerusalem and had reinstituted their covenant responsibilities with God. But, unfortunately, over time, their hearts had once again grown cold regarding the things of their God, and their spiritual lives were lackluster and careless; nor, were they bringing in their tithes as they should have been doing all along. Thus, Malachi represents God’s efforts to call the people back to a true devotion to Himself. These prophesies in Malachi 3 predict more suffering for God’s children until they repent and turn back to God in a latter day (verses 6-10). And yet, though they will be punished for their lack of love for the Lord, God never changes, and it is for this reason that Israel as a nation is not utterly destroyed. In Malachi 3:1, the “messenger” of God is predicted who will precede the Christ, a promise that is partially fulfilled in the coming of John the Baptist, who will prepare the hearts of the people for the coming of the Lord Jesus. However, given the rejection of Christ in Israel (they crucified the Lord), the prophesy also points to the second coming of Christ in judgment upon all unfaithfulness (see Malachi 2:17; 3:2-5), and God further amplifies the reasons for His displeasure with Israel (Malachi 3:7-10).

William Macdonald in his Bible Commentary on Malachi 2:17 says: “They had wearied the Lord by saying that He did not care about the behavior of everyone who did evil. Hypocritically, they challenged Him to intervene, saying, ‘Where is the God of justice?’ (3:6).  The fact that the Lord is the unchanging One accounts for the preservation of the sons of Jacob from destruction.” And yet, my dear friend, despite all of this, God promises better days for Israel…the restoration of His people in their promised land, and God’s blessing forever. This will surely come about in the future day, when God will send Elijah to them, heralding the second coming of Christ in the end times. (See Malachi 4:5; Zechariah 14). Thus, in summary, Israel continued to wander far from the Lord in their hearts, even after their captivity in Babylon, so the Lord will execute more punishment upon Israel. But, since His love for His people never changes, there will be a day of restoration of Israel, with Christ Jesus ruling the world from the throne of David, and the faithful remnant of Israel being blessed in their land forever, just as the covenant with Abraham promised. So, you see, all blessing for God’s people come through Christ Jesus!

But now, at this juncture, I do want to say something about “tithing,” because I believe that some may be confused by the verses in Malachi 3 which refer to the restoration of the ordinances of God including tithing (verses 7-10). Israel had indeed sinned in the OT times by not bringing in the tithe, and thus “robbing God” (verses 8,9). Macdonald in his Bible Commentary summarized the direction of Scripture regarding the New Testament position on giving as opposed to the tithe as follows: “3:7: The NT teaches believers to give systematically, liberally, cheerfully, and as the Lord has prospered them, that is, proportionately. But no mention is made of tithing. Rather, the suggestion is that if a Jew living under law gave a tenth, how much more should a Christian living under grace give!” For more on “giving” in the New Testament, you might also want to take a look at 2 Corinthians 9:7.

There is one last thing for me to say about Malachi. The future blessings of Israel that are spoken of in Malachi 4:5 and in Zechariah 14 are for the faithful remnant of Israel in the latter day. All born again Christians today, however, have an even more glorious hope. We look forward to Christ’s return to the air to receive Christians to Himself in heaven (1 Thessalonians 4:16-18), which will occur well before the judgments of earth.  Thus, we are saved by grace through faith in Christ (Ephesians 2:8,9), and we have the certain hope of heaven (John 3:16; 1 John 4:10). And now, I must ask you…are you saved from the coming judgment? In order for you and me to be saved from the wrath of God because of our sins, we must repent and believe on the Lord Jesus Christ (see John 5:24; Romans 10:9). The blessing of salvation and new life in Christ is for any and all who will believe on the Lord Jesus Christ.  (SF)  (562.6)