The Rebbe says:
1. The Torah says, “Seek Hashem when He is found”. The Talmud tells us that this verse specifically refers to the first ten days of the Hebrew month of Tishrei, beginning with Rosh Hashanah (the first of Tishrei), and concluding with Yom Kippur (the tenth of Tishrei). These ten days are “Days of Repentance”.
2. During these ten days of repentance our Rabbis implemented the addition of Psalm 130 into the daily morning prayers. After the “Verses of Praise” and before the blessings preceding the Shema we say:
“A song of ascents, from the depths I call out to you Hashem. My L-rd, hearken to my voice; let your ears be attentive to the voice of my pleas. G-d, if You were to preserve iniquities, my L-rd, who could survive? But forgiveness is with You, that You may be feared. I hope in the L-rd; my soul hopes, and I long for His word. My soul yearns for the L-rd more than night watchmen waiting for the morning, wait for the morning. Israel, put your hope in the L-rd, for with the L-rd there is kindness; with Him there is abounding deliverance. And He will redeem Israel from all its iniquities”.