Commemorated on March 15
In the Orthodox Church, the last Sunday before Great Lent—the day on which, at Vespers, Lent is liturgically announced and inaugurated—is called Forgiveness Sunday. On the morning of that Sunday, at the Divine Liturgy, we hear the words of Christ:
“If you forgive men their trespasses, your heavenly Father will also forgive you, but if you forgive not men their trespasses, neither will your Father forgive your trespasses…” (Mark 6:14-15).
Then after Vespers—after hearing the announcement of Lent in the Great Prokeimenon: “Turn not away Thy face from Thy child, for I am afflicted! Hear me speedily! Draw near unto my soul and deliver it!”, after making our entrance into Lenten worship, with its special melodies, with the prayer of Saint Ephraim the Syrian, with its prostrations—we ask forgiveness from each other, we perform the rite of forgiveness and reconciliation. And as we approach each other with words of reconciliation, the choir intones the Paschal hymns, filling the church with the anticipation of Paschal joy.
To read more, go to https://www.oca.org/saints/lives/2021/03/15/8-beginning-of-great-lent .