Nunc Sancte, nobis Spiritus,
unum Patri cum Filio,
dignare promptus ingeri
nostro refusus pectori.

Os, lingua, mens, sensus, vigor
confessionem personent,
flammescat igne caritas,
accendat ardor proximos.

Come, Holy Spirit, who ever One
art with the Father and the Son,
it is the hour, our souls possess
with Thy full flood of holiness.

Let flesh, and heart, and lips, and mind,
sound forth our witness to mankind;
and love light up our mortal frame,
till others catch the living flame.

(Part of Hymn for the Third Hour)
(Attributed to St. Ambrose (340-397), this hymn is for the office of Terce (mid-morning prayer, about 9:00 AM) from the Liturgy of the Hours. It is particularly appropriate for Terce, for it was at that hour the Holy Spirit came upon the Apostles on Pentecost (Acts 2:15). English translation by Cardinal Newman (1801-1890).)

Source: http://www.preces-latinae.org/thesaurus/Hymni/NuncSancte.html