The music you are hearing is the traditional Coptic hymn Pek Ethronos or 'his Throne.' The words come from Psalm 45:
Thy throne, O God, is for ever and ever: the sceptre of thy kingdom is a sceptre of righteousness.
Thou hast loved righteousness, and hated iniquity: therefore God, thy God, has anointed thee with the oil of gladness beyond thy fellows.
Myrrh, and stacte, and cassia are exhaled from thy garments, and out of the ivory palaces,
with which kings' daughters have gladdened thee for thine honour: the queen stood by on thy right hand, clothed in vesture wrought with gold, and] arrayed in divers colours.
Hear, O daughter, and see, and incline thine ear; forget also thy people, and thy father's house.
Because the king has desired thy beauty; for he is thy Lord.
And the daughter of
All her glory [is that] of the daughter of the king of Esebon, robed [as she is] in golden fringed garments,
in embroidered [clothing]: virgins shall be brought to the king after her: her fellows shall be brought to thee.
They shall be brought with gladness and exultation: they shall be led into the king's temple.
Instead of thy fathers children are born to thee: thou shalt make them princes over all the earth.
They shall make mention of thy name from generation to generation: therefore shall the nations give thanks to thee for ever, even for ever and ever.