Today, is the feast day of St Michael the Archangel, and all holy angels according to the Byzantine liturgical calendar (as a point of comparison, the Latin Church in her Novus Ordo liturgy, honors St Michael on September 29).
“Angels, archangels, thrones, dominions, principalities, virtues, powers, and the many-eyed cherubim praise you. You are surrounded by the six-winged seraphim; two wings cover their face, two their feet, and with two they fly, and they call one to another with never-ending and never-silent hymns of praise.” [Liturgy of St. Basil the Great]
“Princes of the heavenly hosts, we, though unworthy, beg you to encircle us through your prayers under the shelter of the wings of your spiritual glory. Guard us as we come to you and sincerely cry: Deliver us from dangers, O princes of the powers on high!”
The Church’s teaching on St. Michael is that he is the leader of the good angels, thus holding the title of “Archangel.” Angels are non-corporeal beings created by God. As spirits without bodies they’re invisible to the human eye. By definition, angels bring to us messages because this is one of the ways God communicates with us. Additionally, the “messengers of God” are the guardians of human persons, and their work is to be constantly singing the praise to God.