A.1 For, behold, the day cometh, that shall burn (baar) as an oven;
B. and all the proud, yea, and all that do wickedly, shall be stubble:
A’. and the day that cometh shall burn (lahat) them up, saith the LORD of hosts,
B’. that it shall leave them neither root nor branch.
A.2 But unto you that fear my name shall the Sun of righteousness arise with healing in his wings;
B. and ye shall go forth, and grow up as calves of the stall.
B’. 3 And ye shall tread down the wicked; for they shall be ashes under the soles of your feet
A’. in the day that I shall do this, saith the LORD of hosts.
Note: in these two sections the day of judgment for the wicked is contrasted with the day of salvation for the righteous. Special emphasis is given to the latter, with “the coming of the day” described as the rising of the sun of righteousness, i.e. the coming of Christ.
The macro-chiasm structure of Malachi 4:
AA Lord of hosts comes to destroy the wicked
BB Remember the law given to Moses
AA Elijah comes before the dreadful day of the Lord to turn hearts
Chapter 4 is an apocalyptic prophecy involving three individuals that begins and ends with warnings, and in the center reminds Israel to follow the commandments.
Seeing this structure explains why verse 4 is stuck in the middle of verses 1-2 and 5-6. Without seeing this structure there is no context for verse 4.
I agree with the Note and perhaps a better structure of verses 1-3 is one simple chiasm:
A. 1 For, behold, the day cometh, that shall burn (baar) as an oven;
B. and all the proud, yea, and all that do wickedly, shall be stubble:
C. and the day that cometh shall burn (lahat) them up, saith the LORD of hosts,
D. that it shall leave them neither root nor branch.
E. 2 But unto you that fear my name shall the Sun of righteousness arise with healing in his wings;
D’. and ye shall go forth, leaping like calves from the stall.
C’. 3 And ye shall tread down the wicked;
B’. for they shall be ashes under the soles of your feet
A’. in the day that I shall do this, saith the LORD of hosts.
E not only centers on Christ, but is addressed to “you that fear my name”, which “you” is repeated in D’, C’ B’. A clarifies it is not “you” but the Lord that shall do this.
I also note that the word “shall” is repeated 8 times, which refers to new beginning or resurrection per Bullinger.