In the Liturgy of St. John Chrysostom, used in both the Catholic and Orthodox Churches, there is a part before the reading of the Epistle and the Gospel called the Trisagion, otherwise known as the “Thrice Holy” hymn, which the both the priest and the congregation say or sing
Holy and Mighty
Holy and Immortal
Have Mercy on Us
A musical sample of this can be found in the Greek by clicking here.
It is incredibly easy to glibly go past these words in the liturgy without giving it any further thought. But the 14th century Orthodox Church Father St. Nicholas Cabasilas (pictured above) provides a very important corrective to this. Far from a repetitive hymn (apart from having three “holies”, it is also sung thrice), Cabasilas provides a short but powerful commentary on the ecclesiological, biblical and ultimately cosmological significance of the arrangement of these few words. For Cabasilas, this otherwise short passage is an encapsulation of the whole of Scripture, as well as the whole of the temporal and heavenly orders into a single entity which is the Church. To quote Cabasilas:
The Thrice-holy Hymn has been taken in part from the angels, and in part from Book of Psalms by the Prophet David; it was made into one hymn by the Church of Christ and dedicated to the Holy Trinity. The holy, which is sung three times, belongs to the angels (cf. Isa. 6:3), while God, mighty and immortal come from the blessed David, who says: My soul thirsts for God, the mighty, the living (Ps. 41:3). Our holy church received all this and joined the psalm with the angelic hymn and added the petition, Have mercy on us… in order to show both the harmony of the Old Testament with the New, and that angels and men form one Church and one choir.