The Midrash Talpiyot, based on the Zohar in Parashat Noah, writes that the souls of the wicked condemned to suffering in Gehinam are given a reprieve from their suffering during the times when we are praying here in this world. Each of the three daily prayer services, the Midrash Talpiyot writes, lasts for an hour-and-a-half. (It seems that in the olden days the Sadikim spent a full 90 minutes on each prayer, even Minha and Arbit!) This means that the wicked enjoy 4.5 hours of relief a day (three 90-minute periods), or 27 hours a week (4.5 X 6), excluding Shabbat, throughout which the wicked are in any event given a reprieve. It thus emerges that out of the 144 hours in the workweek (24 X 6), the souls of the wicked spend 117 hours (144 – 27) suffering in Gehinam.
The Book of Shir Hashirim was composed by King Shelomo and contains 117 verses, corresponding to the 117 hours of suffering endured by the souls of the wicked each week. And thus as we end the week, we read this book in case, G-d forbid, we had done something during the week for which we deserve being condemned to Gehinam. Our reading of this book at the end of the week serves as a Tikkun (rectification) for anything we might have done to earn this kind of harsh sentence. King Shelomo wrote this book to atone for the three sins that he committed, violating the Torah’s restrictions on the amount of wives, wealth and horses a king is allowed to have. Each violation is punishable by 39 lashes, and so he composed the 117 Pesukim of Shir Hashirim (39 X 3) to atone for these transgressions.
The simple reason for reading Shir Hashirim as Shabbat begins is because it refers to the Jewish people as a “Kalla” – the Almighty’s bride (“Bati Le’gani Ahoti Kalla”; “Libabtini Ahoti Kalla”), and it thus relates to Shabbat, which is also called a “bride,” as we say in the Friday night prayer, “Bo’i Kala, Bo’i Kala, Bo’i Kala.”
In light of the importance and value of reading Shir Hashirim before Shabbat, everyone should make an effort to arrive at the synagogue on time on Friday afternoon and to participate in the reading. The reading of Shir Hashirim is not a time for socializing or other activities. It is an important part of Tefila in which everyone should participate, especially in light of the fact that, as Hazal teach us, whereas all books of the Tanach are “Kodesh” (holy), the Book of Shir Hashirim is “Kodesh Kodashim” – “holiest of the holy.”