The collected book of Psalms was possibly given its modern shape and division into five parts in the post-exilic period, although it continued to be revised and expanded well into Hellenistic and even Roman times.2nd century BCE, as Baruch uses Sirach (written c.
180 BCE) and is in turn used by the Psalms of Solomon (mid-1st century BCE). 6:1–73 of the Book of Baruch, is sometimes considered a separate book. A genuine Pauline letter, it mentions "Caesar's household," leading some scholars to believe that it is written from Rome, but some of the news in it could not have come from Rome.
Trito-Isaiah (56–66), coming from a still later period, reflects a Palestinian point of view, with the latter chapters in particular addressed to the cultic concerns of the restored community.
The diversity of materials in these chapters suggests multiple authorship.
Although Isaiah pronounced Yahweh’s judgment upon Judah and Jerusalem for their unfaithfulness, he also announced a new future for those who relied on Yahweh.).