Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Council in Trullo; Often Called The Quinisext Council.: Canon LXXVI

Canon LXXVI.

It is not right that those who are responsible for reverence to churches should place within the sacred bounds an eating place, nor offer food there, nor make other sales.  For God our Saviour teaching us when he was tabernacling in the flesh commanded not p. 399 to make his Father’s house a house of merchandize.  He also poured out the small coins of the money-changers, and drave out all those who made common the temple.  If, therefore, anyone shall be taken in the aforesaid fault let him be cut off.

Notes.

Ancient Epitome of Canon LXXVI.

A public house should not be established within the sacred precincts; and it is wrong to sell food there; and whosoever shall do so shall be cut off.

Both Balsamon and Zonaras remark that this canon refers to the vestibule of the church and to the rest of the sacred inclosure, and not to the interior of the church proper, for there no one would ever think of having a shop.