The justice of God requires that he warn the people before they are destroyed. 2 Kings 17:13 says Yet the Lord testified against Israel, and against Judah, by all the prophets, and by all the seers, saying, Turn ye from your evil ways. In the case of the Babylonian captivity, the Lord sent several prophets to warn the people. Lehi, Jeremiah, Ezekiel, Habakkuk, Nahum, Urijah (Jer 26:20-23), Zephanaiah and Obadiah were probably all contemporaries, and all but Obadiah and Nahum are known to have prophesied specifically about the destruction of Jerusalem.