During the Ten Days of Repentance, between Rosh Hashanah and Yom Kippur, there is a complete seven-day week, one Sunday, one Monday, etc. The Arizal ascribes special significance to this period, explaining that proper service on the Sunday of this week accomplishes repentance and correction of sin for every Sunday of the past year, and so for Monday etc.

In addition to correcting past defects, this week also creates spiritual resources for the coming year (for repentance includes regret for the past and resolve for the future): on Sunday we gather strength for spiritually productive Sundays, etc.

Where do we find that these seven days provide resouces for the coming year?

Yom Kippur is actually also called Rosh Hashanah, as indicated by the scriptural phrasing, “On Rosh Hashanah on the tenth of the month.” Chassidut explains that Rosh Hashanah is in an internal mode, and Yom Kippur in an external one. It is evident, then, that the spiritual service of Rosh Hashanah (“the building of the sefirah of malchut”) continues on the following days, reaching completion on Yom Kippur (when the “building of malchut” is accomplished for all the ten sefirot contained in it, i.e. chachmah of malchut, binah of malchut, etc.). All of the Ten Days of Repentance, thus, express the concept of “Rosh Hashanah”; and just as Rosh Hashanah includes all the days of the coming year (analogous to the head’s relationship to the limbs of the body), so do these days. Every moment is precious!

 

(Likkutei Sichot vol. 14, p. 146, Sichat Shabbat Parshat Ha’azinu 5744)