English summary: Chapters 60-62 of the book of Isaiah are considered to be key texts for explaining the origins of the third section of the book in Isaiah 56-66. Hypotheses on the origin of the texts frequently address an unknown post-exilic author called Third Isaiah, who is said to have formulated his calling and his programme in Isaiah 60-62. After Steck rigorously dismissed the postulate of one prophetic individual, the learned character of these texts - which were never conceived as discrete prophetic logia, but rather always seen within a literary context - is examined. Following...