The 14-day dedication festivities, celebrating the completion of the Holy Temple in Jerusalem built by King Solomon, commenced on the 8th of Tishrei of the year 2935 from creation (826 BCE). The First Temple served as the epicenter of Jewish national and spiritual life for 410 year, until its destruction by the Babylonians in 423 BCE.
The 10-day period beginning on Rosh Hashanah and ending on Yom Kippur is known as the "Ten Days of Repentance"; this is the period, say the sages, of which the prophet speaks when he proclaims (Isaiah 55:6) "Seek G-d when He is to be found; call on Him when He is near." Psalm 130, Avinu Malkeinu and other special inserts and additions are included in our daily prayers during these days.
The Baal Shem Tov instituted the custom of reciting three additional chapters of Psalms each day, from the 1st of Elul until Yom Kippur (on Yom Kippur the remaining 36 chapters are recited, thereby completing the entire book of Psalms). Click below for today's three Psalms.