Simeon the elder (on the left hand of Zachariah) carried the infant Christ in his arms at the Presentation of Christ in the Temple.
In the canticle’s lines, “Lord, now You let Your servant depart in peace, according to Your word,” the aged Simeon says he is now ready for death, having seen the Lord’s “salvation, . . . the glory of Your people, Israel.” (Luke 2:29-32)
The canticle of Simeon is heard daily at Vespers, and also at the end of the Prayers of Thanksgiving after Communion. It is also sung when an infant is brought to the Church to be “churched,” or presented, as was the Lord in obedience to the Law.
Get the collection in a handy booklet, A Guide to the Wall of Hymnographers and Poets, by Tracey Edson, available from the parish or from Amazon.com.