A doxology is a short hymn of praise to God in various Christian worship services, often added to the end of canticles, psalms, and hymns. The tradition derives from a similar practice in the Jewish synagogue.
A familiar doxology is the phrase at the end of the traditional Lord's Prayer not found in the original scripture: "For thine is the kingdom, and the power, and the glory, forever and ever, Amen."
Another doxology in widespread use in English is:
Praise God, from Whom all blessings flow;
Praise Him, all creatures here below;
Praise Him above, ye Heavenly Host;
Praise Father, Son, and Holy Ghost. Amen.
This is usually sung to the tune Old 100th.
The tune ‘Old 100th’, is a melody from Pseaumes Octante Trois de David (1551), and is one of the best known melodies in all Christian musical traditions. The melody receives its name from the hymn All Creatures that on Earth do Dwell by William Kethe, a paraphrasing of the 100th psalm of David, which is the most familiar hymn sung to this music. The tune is usually attributed to the French composer Loys Bourgeois (c.1510 – c.1560).Old 100th
click to hear tune
Another common doxology (and often simply called "The Doxology"), used by Catholics, Orthodox, and many Protestants, is the Gloria Patri, so named for its first two words in Latin and addressed to the Trinity:
Gloria Patri, et Filio, et Spiritui Sancto. Sicut erat in principio, et nunc, et semper, et in sæcula sæculorum, Amen.
Glory [be] to the Father, and to the Son, and to the Holy Ghost. As it was in the beginning, is now, and ever shall be, world without end. Amen.
This doxology, as well as praising God, has been regarded as a short declaration of faith in the co-equality of the three Persons of the Holy Trinity.