When the Tzemach Tzedek* was nine years old the Alter Rebbe** said to Him: I received from my Rebbe (the Maggid***) who received from his Rebbe (the Baal Shem Tov) in the name of his well-known Rebbe**** that from the second day of Rosh Chodesh Elul until Yom Kippur we should say three kapitlach Tehillim every day. Then, on Yom Kippur, thirty-six kapitlach: Nine before Kol Nidrei, nine before sleeping, nine after Musaf, and nine after Ne'ila*5.
Whoever did not start on the second day of Rosh Chodesh should start with the Tehillim of the day on which he realizes his omission and complete the missing Tehillim later.
==== Hayom Yom Elul 1
* 3rd Chabad Rebbe, maternal grandchild of the Baal HaTanya.
** Baal HaTanya.
*** Magid of Mezritch.
**** Achiya Hashiloni.
*5 The Kehot Tehillim has a chart for the Elul-Tishrei Tehillim.
