Albert Barnes Commentary Nehemiah 9:26

"Nevertheless they were disobedient, and rebelled against thee, and cast thy law behind their back, and slew thy prophets that testified against them to turn them again unto thee, and they wrought great provocations." — Nehemiah 9:26 (ASV)

Killed your prophets - Compare (1 Kings 18:4); (1 Kings 19:10); (2 Chronicles 24:21). Jewish tradition further affirms that more than one of the great prophets (e.g., Isaiah, Jeremiah, and Ezekiel) were martyred by their countrymen.