Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Councils of Ancyra, Gangra, Neocæsarea, Antioch and Laodicea, which Canons were Accepted and Received by the Ecumenical Synods.: Canon XXXV

Canon XXXV.

Christians must not forsake the Church of God, and go away and invoke angels and gather assemblies, which things are forbidden.  If, therefore, any one shall be found engaged in this covert idolatry, let him be anathema; for he has forsaken our Lord Jesus Christ, the Son of God, and has gone over to idolatry.

Notes.

Ancient Epitome of Canon XXXV.

Whoso calls assemblies in opposition to those of the Church and names angels, is near to idolatry and let him be anathema.

Van Espen.

Whatever the worship of angels condemned by this canon may have been, one thing is manifest, that it was a species of idolatry, and detracted from the worship due to Christ.

Theodoret makes mention of this superstitious cult in his exposition of the Text of St. Paul, Col. ii. 18, and when writing of its condemnation by this synod he says, “they were leading to worship angels such as were defending the Law; for, said they, the Law was given through angels.  And this vice lasted for a long time in Phrygia and Pisidia.  Therefore it was that the synod which met at Laodicea in Phrygia, prohibited by a canon, that prayer should be offered to angels, and even to-day an oratory of St. Michael can be seen among them, and their neighbours.”

In the Capitular of Charlemagne, a.d. 789 (cap. xvi.), it is said, “In that same council (Laodicea) it was ordered that angels should not be given unknown names, and that such should not be affixed to them, but that only they should be named by the names which we have by authority.  These are Michael, Gabriel, Raphael.”  And then is subjoined the present canon.  The canon forbids “to name” (ὀνομάζειν) angels, and this was understood as meaning to give them names instead of to call upon them by name.

Perchance the authors of the Capitular had in mind the Roman Council under Pope Zachary, a.d. 745, against Aldebert, who was found to invoke by name eight angels in his prayers.

It should be noted that some Latin versions of great authority and antiquity read angulos for angelos.  This would refer to doing these idolatrous rites in corners, hiddenly, secretly, occulte as in the Latin.  But this reading, though so respectable in the Latin, has no Greek authority for it.

p. 151 This canon has often been used in controversy as condemning the cultus which the Catholic Church has always given to the angels, but those who would make such a use of this canon should explain how these interpretations can be consistent with the cultus of the Martyrs so evidently approved by the same council; and how this canon came to be accepted by the Fathers of the Second Council of Nice, if it condemned the then universal practice of the Church, East and West.  Cf. Forbes, Considerationes Modestæ.