When it is said
The old Latin service books give it for the moment visitors arrive at the house.
Pray it when friends come over, before you meet a friend, or whenever you pray for the friends you have.
Where it comes from
No author known
A prayer with no name of its own
The prayer comes from the Old Gelasian book, a Latin service book copied about AD 750 from older prayers of the Church of Rome. It has no name there, so “The Prayer for Friendship” is ours. The prayer that follows it in the book asks God to send the spirit of love, so that His grace grows in us whenever our brothers and fellow servants arrive.
H. A. Wilson, The Gelasian Sacramentary (1894), pages 284 and 285; The Cult of Saints, University of Oxford, record E07005
Kindness or love?
In a later Latin service book from the time of Charlemagne, the same prayer is set for the arrival of brothers who come to visit. Where the older book says God comforts us with “brotherly kindness”, this one says “brotherly love”. William Bright followed the later reading when he put the prayer into English in 1864.
H. A. Wilson, The Gregorian Sacramentary under Charles the Great (1915), page 196; William Bright, Ancient Collects (1864), page 174
The Scripture in it
No one has ever seen God; but if we love one another, God remains in us, and His love is perfected in us.
Bible text: Berean Standard Bible, public domain.
In Latin
Deus humilium visitator, qui nos fraterna dignatione consolaris,
praetende societati nostrae gratiam tuam,
ut per eos, in quibus habitas, tuumque nobis sentiamus adventum.
Per.
From the Gelasian Sacramentary, ed. H. A. Wilson (Oxford, 1894), page 284, on archive.org.