The Book of Chronicles (Divrei Hayamim) is historical in nature but often adds new facts to previously recorded events in Tanach. One example of this is when Dovid HaMelech returns the captured Aron from the Plishtim to the City of David (Shmuel Bais 6:14-22).
When the event is described, we know there was jubilance, but there was no mention of any specific songs that were sung. Divrei Hayamim fills in this gap (16:8-22) by informing us that it consisted of the first 15 verses of Chapter 105 in Tehillim. These are the pesukim we say right after Baruch She’amar in pesukei d’zimra, showing their importance in the area of praising G-d.
The largeness of the event, a dance procession with the Aron, would fittingly be accompanied by a moving song, and indeed, the first 15 verses of Chapter 105 of Tehillim are celebratory.
These 15 verses encapsulate history and tell us the necessary elements needed to serve G-d properly, namely, to give gratitude and express praise. This is all towards the aim of having the Creator reveal Himself to the world at large with unity and splendor.
Within the 15 verses lie the terms of the words malchios (mi’mamlacha, 105:13), zichronos (zecher, ibid. 8), and shofrot (tariu, ibid. 15, hinting to the teruah of the shofar). These verses rightly point to Rosh Hashanah, a time of thanking and praising the King, who we look to for a good judgment. To receive favor with the King, you must first crown Him by recognizing His grandeur.
The fact that the word teruah represents shofrot is in order, as Rosh Hashanah is called by that name (Vayikra 23:24; Bamidbar 29:1), and it’s a reminder to break our ego and middot just as the shevarim are broken sounds.
Chronicling history is one thing, but Divrei Hayamim goes beyond that: it offers new historical facts that were not previously known. We now know the 15 verses that David sang when he reunited with the Aron, verses that we praise G-d early on with every day, and verses that direct us to the kinds of themes we must be thinking about on Rosh Hashanah.