The rhetorical function of Isaiah 1–66 has received limited attention with scholars more interested in examining the rhetoric of themes or sections rather than the book. While some refer to Isaiah’s structure to support a rhetorical function of ‘repentance and reconciliation’ (O’Connell) or ‘envisioning the future’ (Conrad), greater attention needs to be given to Isaiah’s style and emotional content. Style (how a text is written) either helps or hinders readers’ ability to accept the text’s content. Also, augmenting the cognitive content with the emotional content, values the role of the emotions in persuasion. This develops Wenham’s rhetorical-critical methodology to produce a thicker description of a text’s rhetorical function. This paper examines the stylistic, cognitive, and emotional dimensions for four of Isaiah’s rhetorical strategies. First, Isaiah’s opening characterisation of YHWH as a faithful parent, Israel as YHWH’s rebellious child, and the nations as willingly going to YHWH for instruction, establishes that Isaiah’s rhetorical function fundamentally pertains to the relationship between YHWH and people. Second, the self-involvement of readers, via the ‘we’ character, accentuates Isaiah’s rhetorical force on readers. Third, binary images such as light/darkness, up/down, and rejoicing/mourning utilise everyday experience to ground Isaiah’s rhetorical function as describing how to live (walk) in relationship with YHWH. Fourth, Isaiah’s structure confirms the movement, within and across the book, from broken to restored relationship between YHWH and his faithful community. The urgency of the appeal to walk in the light of YHWH resounds throughout Isaiah. YHWH is the everlasting light who alone lights the way to the destination of living in utopic Zion, with YHWH, forever. Isaiah’s blunt alternative is that the darkness of hasty self-determination leads to mourning and the judgment of death.