Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Synods of Sardica, Carthage, Constantinople, and Carthage Under St. Cyprian, Which Canons Were Received by the Council in Trullo and Ratified by II. Nice.: Canon XXII

Canon XXII.  (Greek xxv.)

That bishops or other clergymen shall give nothing to those who are not Catholics.

And that to those who are not Catholic Christians, even if they be blood relations, neither bishops nor clergymen shall give anything at all by way of donation of their possessions.

Notes.

Ancient Epitome of Canon XXII.

Bishops and clergymen shall give nothing of their goods to heretics, nor confer aught upon them even if they be their relatives.

This is Canon xiv. of Hippo, 393.