What the Bible says about Evil Unpunished
(From Forerunner Commentary)
These two verses really form one thought, which is that God allows man to labor in futility, in vain, to prove a greater point and to show the tremendous contrast between man's way and His way. Verse 14 supplies the reason for this vast difference, as well as making a wonderful promise. God allows evil to go seemingly unpunished because He is showing the stark contrast between man's way and His way, and He promises that one day He will make things right by absolutely flooding this world with the knowledge of His way.
Richard T. Ritenbaugh
Habakkuk