September 29 is the feast day of Saint Michael and All Angels. The story of the war in heaven, where St. Michael kills a dragon, is told in Revelation 12:7-12. The Archangel Michael is leader of God's angelic army, also appearing in the Old Testament in the Books of Daniel and Joshua (though he is unnamed there). Much of the other information about him is found in the apocryphal Book of Enoch.
However, the feast day encompasses all angels, the few others that have names and the legions of angels who are not named. Michael's compatriots Gabriel, Raphael, and Uriel have come down to us in scripture and other works, from Haydn's The Creation, where they narrate and comment on the six days of creation, to a number of hymns.
The unnamed angels are probably the ones we think of first, though, and they also frequently appear in hymns. and Christmas carols.
Around the throne of God a band
Of bright and glorious angels stand;
Sweet harps within their hands they hold,
And on their heads are crowns of gold.
Some wait in service, ready still
To sing God's praise and do God's will,
And some, when God commands them, go
To guard the pilgrims here below.
God, give thine angels every day
Command to guard us on our way,
And bid them every evening keep
Their watch around us while we sleep.
So shall no threatening thing draw near
To do us harm or cause us fear;
And we shall dwell, when life is past,
With angels round thy throne at last.
John Mason Neale, 1842; alt.
Tune: WINCHESTER NEW (L.M.)
Musikalisches Handbuch, 1690; harm. William H. Monk, 1847