When it is not combined with Parashat Nitzavim, Parashat Vayelech is read on Shabbat Shuvah just before Yom Kippur, the Day of Atonement. This is fitting as the parashah and the special haftarah for Shabbat Shuvah quoted above, share the familiar yet complex leitmotif of the Jewish people's repeated sinning, God's divine punishment and the redemptive hope, both divine and human, of teshuvah, repentance and return.
On Yom Kippur when Jews engage in deeply reflective prayers of confession and forgiveness, the concept of teshuvah is impoverished if understood solely in terms of God's strict rejection of a person who has sinned.
An adequate notion of teshuvah must include the broader aspects of the individual's return and God's acceptance.
This creates a dynamic process which, through profound often painful regret and prayer, helps the person to acknowledge their wrongdoing, and to strengthen their resolve to act differently in the future, especially when they find themselves in exactly the same situation.