In recent years, the phenomenon of allusion has attracted increasing attention in scholarly study of the Hebrew Bible. The Mouth of the Lord Has Spoken is a detailed and comprehensive analysis of allusions in Isaiah 40-66. Author Risto Nurmela explores how allusions are identified through verbal similarities in biblical passages and how this information is used to prove that the similarities are the result of literary dependence. This work independently scrutinizes the verbal similarities between Isaiah 40-55 and the rest of the Hebrew Bible and Isaiah 56-66 and the rest of the Hebrew Bible. The Mouth of the Lord Has Spoken is an important contribution to the ongoing discussion of allusions in the Hebrew Bible.