Holy God, Holy Mighty, Holy Immortal, have mercy on us. (Read three times, with the sign of the cross and bow from the waist.)
Holy is holy.
+ This is a prayer to the Three Persons of the Holy Trinity. By the words Holy God we mean God the Father; under the words Holy Mighty - God the Son (He is Mighty, or All-Powerful, since by His resurrection He destroyed hell and defeated the devil; the coming Lord Jesus Christ is called Mighty God by the prophet Isaiah - chapter 9, verse 6: For to us a child is born - to us a Son is given; Dominion is on His shoulder, and His name will be called: Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace); under the words: Holy Immortal - God the Holy Spirit (He, like God, is eternal, and He is the Life-giving Spirit: He gives life to everyone, and especially spiritual, virtuous life and immortality to people). Since all Three Persons constitute the One and Undivided God, the conclusion of the prayer contains a singular verb - have mercy on us - refers to the same Being of God.
+ The story of this prayer is wonderful. In the 5th century there was a terrible earthquake in Constantinople. All the people cried and prayed to God. During a national prayer service, one boy was lifted high into the air by an invisible force, and then lowered to the ground unharmed. The boy could not answer where he was and what he saw; he only heard the harmonious and touching singing: “Holy God! Holy Mighty! Holy Immortal! The people realized that this was the singing of Angels, and everyone began to sing the same words, adding: “Have mercy on us!” - and the earthquake stopped. God had mercy on His people. Since then, this song began to be used by Christians. It is sung and read in the Church at every church service. It is also called the Angelic Song to the Most Holy Trinity.
Song of the Angels “Holy, Holy, Holy is the Lord God!” The prophet Isaiah also conveyed to us: Seraphim stood around Him; each of them had six wings: with two he covered his face, and with two he covered his feet, and with two he flew. And they called to each other and said: Holy, Holy, Holy is the Lord of hosts! The whole earth is full of His glory! (Isa.6:2-3). This vision is repeated in the Revelation (Apocalypse) of St. John the Theologian: ... in the middle of the throne and around the throne were four living creatures, full of eyes in front and behind ... And each of the four living creatures had six wings around, and inside they were full of eyes; and they have no rest day or night, crying out: Holy, holy, holy is the Lord God Almighty, who was, who is, and who is to come (Rev. 4:6-8). This Angelic song, in which God is called the Holy One three times, was one of the first messages about the great mystery of the Trinity of the Divinity.
“The Holy Seraphim, through the triple Holy, announce to us the Three Persons of the all-essential Divinity. And through one dominion they proclaim both the one essence and the one Kingdom of the Divine Trinity.”
Venerable John of Damascus.
"An Accurate Statement of the Orthodox Faith"
Definition of Deity God, the Mighty, the Immortal, according to the observation of St. John of Damascus, also stand side by side in Ps.41, verse 3: My soul thirsts for the Mighty, living God. And finally, the Trisagion is concluded with the popular cry of the Church, its most frequent prayer: have mercy on us!
“We understand the words Holy God about the Father, not only separating the name of the Divine from Him, but knowing Him as God, and the Son, and the Holy Spirit. And we understand the words “Holy Mighty” about the Son, without depriving the Father and the Holy Spirit of strength. And we relate the words Holy Immortal to the Holy Spirit, not placing the Father and the Son outside of immortality, but regarding each of the Hypostases, accepting all the Divine names simply and independently and truly, imitating the divine Apostle, who says: We have one God the Father, from whom are all things, and we for Him, and one Lord Jesus Christ, by whom are all things, and we by Him (1 Cor. 8:6), and one Holy Spirit, in whom are all things and we in Him."
Venerable John of Damascus.
"An Accurate Statement of the Orthodox Faith"
Glory to the Father, and the Son, and the Holy Spirit, now and ever, and unto ages of ages. Amen.
Ever - Always; forever and ever - forever.
+ This is a short, or small doxology. It means that the same glory and worship belongs to the Father, the Son, and the Holy Spirit, and not only now, but always, as the One, Eternal God, in all ages, in all generations, constantly and unchangeably.
+ “God is One in Three Persons. We do not comprehend this inner mystery of the Divinity, but we believe in it according to the immutable testimony of the word of God: No one knows the things of God except the Spirit of God (1 Cor. 2:11).”
Saint Philaret.
"Long Christian Catechism"
In prayer books and liturgical books, this prayer, since it is often used, is often abbreviated: Glory, and now: (or Glory: And now:). In such cases, one should read in full: Glory to the Father, and to the Son, and to the Holy Spirit, now and ever, and unto ages of ages. Amen.
Meeting the abbreviation Glory:, we read: Glory to the Father, and the Son, and the Holy Spirit, meeting the abbreviation And now: - And now and ever and unto ages of ages. Amen.