Albert Barnes Commentary Jeremiah 51:46

"And let not your heart faint, neither fear ye for the tidings that shall be heard in the land; for tidings shall come one year, and after that in another year [shall come] tidings, and violence in the land, ruler against ruler." — Jeremiah 51:46 (ASV)

Literally, And beware lest your heart faint, and you be afraid because of the rumor that is heard in the land: for in one year shall one rumor come, and afterward in another year another rumor; and violence shall be in the land, and so on. The fall of Babylon was to be preceded by a state of disquiet. People’s minds were unsettled, partly by rumors of the warlike preparations of the Medes and of actual invasions, and partly by internal feuds. So, before the conquest of Jerusalem by the Romans, the Church had similar warnings (Matthew 24:6–7).