I sanctified — I ordained thee for this public service. He speaks thus to Jeremiah, not to the other prophets, because he stood in need of greater encouragement than they, both in respect of the tenderness of his years, and the difficulties which he was to encounter with. The nations — To other nations besides the Jews.
Related Commentaries of Jeremiah 1:5
Jeremiah 1:5
5 Before I formed thee in the belly I knew thee; and before thou camest forth out of the womb I sanctified thee, and I ordaineda thee a prophet unto the nations.