To whom He said: or, He (Jehovah) Who said to them: i.e. by His prophets (Isaiah 7:4; Isaiah 8:6; Isaiah 30:15).
Related Commentaries of Isaiah 28:12
Isaiah 28:12
12 To whom he said, This is the rest wherewith ye may cause the weary to rest; and this is the refreshing: yet they would not hear.