Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Fourth Ecumenical Council.  The Council of Chalcedon.: Canon XI

Canon XI.

We have decreed that the poor and those needing assistance shall travel, after examination, with letters merely pacifical from the church, and not with letters commendatory, inasmuch as letters commendatory ought to be given only to persons who are open to suspicion.

Notes.

Ancient Epitome of Canon XL.

Let the poor who stand in need of help make their journey with letters pacificatory and not commendatory:  For letters commendatory should only be given to those who are open to suspicion.

Aristenus.

…The poor who need help should journey with letters pacificatory from the bishop, so that those who have the ability to help them may be moved with pity.  These need no letters commendatory, such letters should be shown, however, by presbyters and deacons, and by the rest of the clergy.

See notes on canons vij., viij., and xj. of Antioch; and on canon xlij. of Laodicea.

Hefele.

The mediaeval commentators, Balsamon, Zonaras, and Aristenus, understand this canon to mean that letters of commendation, συστατικαὶ , commendatitiæ litteræ were given to those laymen and clerics who were previously subject to ecclesiastical censure, and therefore were suspected by other bishops, and for this reason needed a special recommendation, in order to be received in another church into the number of the faithful.  The letters of peace (εἰρηνικαί) on the contrary, were given to those who were in undisturbed communion with their bishop, and had not the least evil reputation abroad.

Our canon was understood quite differently by the old Latin writers, Dionysius Exiguus and Isidore, who translate the words ἐν ὑπολήψει by personæ honoratiores and clariores, and the learned Bishop Gabriel Aubespine of Orleans has endeavored to prove, in his notes to our canon, that the litteræ pacificæ were given to ordinary believers, and the commendatitiæ (συστατικαί) on the contrary, only to clerics and to distinguished laymen; and in favour of this view is the xiii. canon of Chalcedon.

With regard to this much-vexed point, authorities are so divided that no absolute judgment can be arrived at.  The interpretation I have followed is that of the Greeks and of Hervetus, which seems to be supported by Apostolic Canon XIII., and was that adopted by Johnson and Hammond.  On the other hand are the Prisca, Dionysius, Isidore, Tillemont, Routh, and to these Bright seems to unite himself by saying that this “sense is the more natural.”