Chant and do not stop chanting, and for this I will not abandon you.
St. John Koukouzelis the angel-voiced (celebrated Oct 1/14) is one of the patron saints of chanters. He lived c. 1270-1340 and it is believed that he was first the principal chanter in the imperial court in Constantinople, and later a monk and chanter at the monastery of the Great Lavra on the Holy Mountain, Mount Athos.
Twice in his life our Holy Mother of God, whom we lovingly call the Panagia (the All-Holy), appeared to St. John Koukouzelis. On the first occasion, St. John had just finished fervently chanting the Akathist Hymn to the Most Holy Mother of God in front of her holy icon and sat down in one of the stalls. Being very tired, he soon was asleep. Suddenly he heard the voice of our Holy Mother of God saying to him "Rejoice, John! Chant and do not stop chanting, and for this I will not abandon you." Our Panagia was standing in front of John, glowing with heavenly light. She placed a gold coin in John's hand, and then disappeared. When John awoke, the gold coin remained in his hand. He placed it on the icon before which he had chanted and received this vision. This miraculous icon, which to this day is kept in a chapel of the Great Lavra, came to be known as the Panagia Koukouzelissa icon.
With the blessings of our Holy Lady, St. John continued to chant more fervently than before. His severe asceticism and strict discipline of standing during the long services caused his legs to swell and become covered with infected sores full of maggots. Yet again our beloved Panagia came to John, appearing in a dream to sweetly say "From now on, be healthy!" St. John's legs were miraculously healed, and in gratitude he spent the rest of his life fully dedicated to God in his asceticism, fasting, and long vigils.
Through the prayers of our Holy Father in the ascetic life, St. John Koukouzelis the angel-voiced, and through the intercessions of our Most Holy Lady the Mother of God, may Lord Jesus Christ our God have mercy on us and save us. Amen.
icon taken from St. Anthony's Divine Music Project - http://www.stanthonysmonastery.org/music/Chrys/bm1550_Let%20our%20Mouths%20be%20Filled.pdf