Psalms, formation of the book of
Hezekiah's men copied out (and put in final form?) some of the
proverbs of Solomon (Pro 25:1). Hezekiah was a man consumed with zeal for the
Lord's house and the worship of God there. Hezekiah "commanded the Levites to
sing praise to the Lord with the words of David and of Asaph the seer" (2Ch
29:30). This may mean that he authorized the use of an old collection (David's)
as well as a new collection (Asaph's) of Temple songs. This all suggests that
Hezekiah and dedicated men under his direction organized and reissued the older
psalms, and supplemented the collection with newer ones (including those of
Hezekiah himself: see GB, "Songs of Degrees" 102-104)... to produce a "hymnal"
to supplement the Sabbath readings of Scripture in the Temple; hence the "5
books" of Psalms.
Thus Hezekiah was virtually the "editor" of the Psalter. (The
Talmud has attributed to him the final preparation also of Isaiah, Proverbs, the
Song of Songs, and Ecclesiastes.)
Only kings (such as David and Hezekiah) would have the
authority to organize and direct scribes, Levites, priests, and musicians in
such a great undertaking. And David and Hezekiah were patrons of the worship of
the Lord.
It is also possible that Hezekiah made inspired additions to
the text of some of David's psalms, to fit them to his own similar, though not
identical, circumstances.