The Sages in Bava Kama 50a bring a verse from Parashat HaAzinu that proves that everyone needs to do TeShuva. Rabbi Yaron Reuven says, this means everyone from gentiles to the greatest Rabbis need to do TeShuva. Rabbi Reuven lays out a path to start your TeShuva and get real emunah in HaShem through the difficulties.