This Gospel canticle is one of three recited daily in the breviary. The other two are Zechariah’s Benedictus and Mary’s Magnificat. These three canticles found passage also from the Brevarium Romanum into the Liturgy of the Hours, though with slight modification. This particular text is the prayer of Simeon. The Holy Family enters the temple, and Simeon, moved by the Holy Spirit, greets them with this song.

Nunc dimittis servum tuum = Now you dismiss your servant. He is an old man, at the end of his life, and a servant of God (servus Dei). Now he is ready to die. His mission is complete.

secundum verbum tuum = according to your word. God had promised Simeon, given His word (verbum) that he would see the savior before dying, and upon seeing the infant Christ, in the arms of Mary, he realizes the day has come.

in pace = in peace. There is peace in God’s will, and in the fulfillment of His promises.