The First Friday devotion and the First Saturday devotion are both reparatory devotions in the Catholic Church that arose from separate private revelations. The First Friday devotion is associated with the Sacred Heart of Jesus, while the First Saturday devotion is associated with the Immaculate Heart of Mary. Incidentally, these are two of the most widely popular devotions to Jesus and Mary.
Both devotions involve receiving Holy Communion on a certain number of consecutive first Fridays or first Saturdays of the month.