The texts in the prophetic books which suggest a consciousness of the power of the divine word form the starting-point for an investigation of prophetic discourse in these books in terms of J.L. Austin and J.R. Searle's theory of speech acts. R.P. Carroll's suggestions on the topic are critically examined, and a study is then undertaken of judgement prophecy to demonstrate that it should be understood as having the illocutionary force of a declaration placing the hearers (or a third party) under judgement. The response narrated or expected to such prophecies in prophetic narratives is shown to be ambiguous as between mourning over an accomplished act of judgement and prayer for mercy, and this is seen to be appropriate to an illocutionary act of that kind.