Zechariah 1:5-6

The lesson conveyed by these two verses, which must be taken together, is the same as that contained in the words of Isaiah (Isaiah 40:6; Isaiah 40:8), "All flesh is grass, and all the goodliness thereof is as the flower of the field … The grass withereth, the flower fadeth, but the word of our God shall stand for ever." There, however, the lesson has reference to God's word of promise, for comfort (comp. 1 Peter 1:24-25). Here it has reference to His word of threatening, for warning.