From Gal 5:22. See CCC 1832

This prayer is from the "Teaching of the Twelve Apostles", otherwise known as the Didache. The Didache is a second century document written in Jerusalem (ca 140 AD) and contains a summary of the catechesis of the Twelve Apostles. It was used in the early Church for the instruction of the catechumens and was highly valued as a source of instruction and inspiration in the early Church. Today it gives us important insight into the teachings and practices of the early Church

Popular tradition maintains that this little prayer was given by St. Anthony to a poor woman who was troubled by temptations. It has been popular prayer amongst Franciscans for centuries. Pope Sixtus V, a Franciscan himself, had the prayer carved at the base of the obelisk, which he erected in St. Peter's Square in Rome in 1585.

Attributed to Pope St. Gregory the Great (540-604), but some think it may be a later composition by Alcuin (732-804). In the current Liturgia Horarum it is used for Laudes for the Sundays of the second and fourth weeks of the Psalter during Ordinary Time. In the Roman Breviary it is used for Lauds on the fourth and subsequent Sundays after Pentecost until September 27 inclusive.

There are two Pange Linguas in use, one by St. Thomas Aquinas and then this one, by Venantius Fortunatus (530-609) which extols the triumph of the Cross. He wrote it for a procession that brought a part of the true Cross to Queen Radegunda in 570. This hymn is used on Good Friday during the Adoration of the Cross and in the Liturgy of the Hours during Holy Week and on feasts of the Cross. The concluding stanza was not written by Fortunatus, but was added later.
When used in the Liturgy the hymn is often broken into smaller hymns such as: Lustra sex qui iam peregit, En acetum, fel, arundo, and Crux fidelis inter omnes.
There is a charming ancient legend that is hinted at in the second verse of this hymn. According to this legend, the wood of the Cross upon which Christ was crucified was taken from that tree which was the source of the fruit of the fall in the Garden of Eden. When Adam died, the legend states, Seth obtained from the Cherubim guarding the Garden a branch of the tree from which Eve ate the forbidden fruit. Seth planted this branch at Golgotha (the place of the skull), which is so named because Adam was buried there. As time went on, the Ark of the Covenant, the pole upon which the bronze serpent was lifted, and other items were made from this tree.

This prayer calls to mind Psalm 21, in particular verses 17 and 18, which concern our Lord's Passion. A plenary indulgence is granted to the faithful on any Friday of Lent or Passiontide who after Communion piously recite this prayer before an image of Christ crucified. On other days of the year the indulgence is partial.

Attributed to Pope St. Gregory the Great (540-604). In the Roman Breviary this hymn is used in its entirety for Matins from the first Sunday in Lent until the Saturday before Passion Sunday. Today the hymn is still used, but from Ash Wednesday until the Fifth Sunday of Lent and it is broken into two hymns. The first half, Ex more docti mystico, is used for the Sunday Office of the Readings. The second half, Precemur omnes cernui is used for Sunday Lauds. Both those hymns conclude with the final verse as found below.

This prayer from the Roman Ritual is graced with a partial indulgence.

As practiced by the Franciscans and extracted from the writings of St. Francis of Assisi. The English is from a Franciscan booklet and diverges from the Latin in places, but is otherwise a respectable translation.

Taken from the Coeleste Palmetum, 1741, 1872, and 1890 editions.