Hashgachah Pratis in the Sefarim Hakedoshim
When a Yid has done teshuvah, he is a completely new person. Teshuvah has the power to turn over entire worlds. But of course, the yetzer hara is not pleased with this situation. It tries to make each person surrender to his sins, and to minimize the power of his teshuvah. But the truth is exactly as Rabbeinu Yonah writes in the beginning of Shaarei Teshuvah (9): For every teshuvah, there is forgiveness. The difference between a person before the forgiveness and that same person after the forgiveness cannot be measured.
The more a person continues to feel that his sins have not been forgiven and erased and does not believe that he has effected a tremendous change in himself, he discounts the power of teshuvah and continues sinning. On the other hand, someone who accepts his own teshuvah with joy, who is happy and believes that his teshuvah was accepted, opens a new page and helps himself to improve more and more.
We have a principle that anything’s value is determined by the chashivus people give it. This applies to teshuvah as well: The more a person values his own teshuvah as something genuine and believes that all his sins can be forgiven through it, the more value his teshuvah has.
The Rambam (Hilchos Teshuvah 7:4) wanted to prevent negative thoughts about the truth of teshuvah, and therefore he wrote, in his unique way, that a person should not think that he is distant from the levels of the tzaddikim because of his sins, for this is not so. Rather, he is beloved by the Creator. Moreover, even genuine tzaddikim cannot reach the level of a person who repented sincerely.
During Aseres Yemei Teshuvah, and especially on Shabbos Shuva, we need to trust in Hashem that He will accept our teshuvah, and to recognize and give thanks for the great gift of teshuvah.
Excerpts from the popular shiur by Harav Yehuda Mandel shlit”a from Lakewood