Charles Ellicott Commentary Jeremiah 28:9

"The prophet that prophesieth of peace, when the word of the prophet shall come to pass, then shall the prophet be known, that Jehovah hath truly sent him." — Jeremiah 28:9 (ASV)

The prophet who prophesies of peace.—“Peace,” with its Hebrew associations, includes all forms of national prosperity, and is therefore contrasted with famine and pestilence, not less than with war. The obvious reference to the test of a prophet’s work, as described in Deuteronomy 18:22, shows, like other similar references, the impression that book had made on the prophet’s mind.