He is saying, "Go through the temple rituals and perform all your sacrifices. It does not mean a thing to Me because your attitude is rotten! You do not realize who I am. You are just going through the motions!"
John O. Reid (1930-2016)
The halfhearted service, the halfhearted obedience, and the profanation are evident. The sacrifices that were being offered to God were being done in a way that was not acceptable to Him.
There is no indication that what these people were doing was deliberate. It seems that it was not a reasoned conclusion that it should be done this way. They were not purposefully worshipping God this way. It was not in their heart to do it! But it was nonetheless being done that way. They were treating God as though He and the things of the altar—the service and the sacrifice of the altar—were less important than other things. The way they performed the ritual showed that in their hearts they considered it a secondary matter. Other things were squeezing out what should have been their first priority.
John W. Ritenbaugh
The Fourth Commandment (Part 4)
How does God react to those who should know better but live before Him a poor-quality life? Malachi 1:6-10 pictures God's reaction—He is not pleased.
Here God indicts the people of Malachi's day for offering inferior, sometimes even deformed animals on His altar! The spiritual parallel concerns the offering of our lives in service to Him and fellowman. Are we, out of love for God and His people, giving the best we have to offer in life's circumstances? Solomon admonishes in Ecclesiastes 9:10, "Whatever your hand finds to do, do it with your might; for there is no work or device or knowledge or wisdom in the grave where you are going." A Protestant hymn, "Give of Your Best to the Master," expresses this requirement well. Though God accepts us because of Jesus Christ, He expects us to give the very best we can in return.
John W. Ritenbaugh
The Offerings of Leviticus (Part Four): The Peace Offering
Other Forerunner Commentary entries containing Malachi 1:10: