Today's Gospel is from St Matthew 5:20-24, the Sermon on the Mount. The Magnificat antiphon at I Vespers refers to 2 Kings (Samuel), which is started today at Matins.
Today is also the memorial of Pope St. Leo IV, whose pontificate lasted from 847 to 855. A Roman by birth, he was a Benedictine monk who served in the papal curia under Pope Gregory IV, was made a cardinal by Pope Sergius II and was unanimously chosen to succeed him.
His main claim to fame relates to his efforts to defend Rome against Muslim attacks.
He had defensive walls built, including around St. Peter's, and repaired much of the damage done by attacks during the reign of his predecessor.
When the Muslim fleet again threatened, he rallied the leaders of Rome, Naples, Gaeta and Amalfi to form a league. The subsequent Battle of Ostia (depicted above in a painting by Raphael or his disciples, with the Pope at the left), in which the attacking Saracen force was destroyed, was one of the most famous in the history of the papacy during the Middle Ages.
St Leo held three synods, including one in 850, that was distinguished by his crowning of the Holy Roman Emperor Louis II. He also reportedly anointed the young King Alfred the Great of England.
St Leo's papacy is also noted for his attempts to bring rebellious bishops and political leaders into line with Rome. He excommunicated Cardinal Anastasius of San Marcello (later Antipope Anastasius Bibliothecarius) for disobedience and censured the soon to be famous Archbishop Hincmar of Reims.