You only have I known of all the families of the earth: therefore I will punish you for all your iniquities.
You only have I known - i:e., acknowledged as my people, and treated with special favour (Exodus 19:5; Deuteronomy 4:20). Compare the use of "know," Psalms 1:6; Psalms 144:3; John 10:14; 2 Timothy 2:19.
Therefore I will punish. The greater the privileges, the heavier the punishment for the abuse of them: for to the other offences there is added, in this case, ingratitude. When God's people do not glorify Him, He glorifies Himself by punishing them.