In chapter 36 of The Apostolic Tradition, we read the following in the various recensions of the text (the following comes from Paul F. Bradshaw, Maxwell E. Johnson, and L. Edward Phillips, The Apostolic Tradition: A Commentary [Hermeneia—A Critical and Historical Commentary on the Bible; Minneapolis: Fortress Press, 2002], 180-81):
Latin: every faithful [person]
take care to receive the Eucharist before he tastes anything else. For if he
receives in faith, even if something deadly shall be given to him after this,
it cannot harm him.
Sahidic: Concerning that it is
proper to receive the Eucharist (ευχαριστια)
early at the time it will be offered up, before they taste anything.
And (δε) let
every faithful [person] (πιστος) hasten (σπουδαζειν) to receive the Eucharist (ευχαριστια) before he tastes anything. For (γαρ) if there are some faithful (πιστος) who receive it, if someone gives
him (sic) a drug, it will not affect him.
Arabic: That they should receive
the Eucharist first, at the time when it takes place, before tasking anything
Every believer should make it his
practice that he should receive the mysteries before tasting anything. If there
is faith in him and he receives it, if someone gives him deadly poison, it will
not hurt him.
Ethiopic: Concerning that it is proper
for them to receive the Eucharist first when they go up, before they taste
anything.
Every believer is to carry out the
admonition that he receives from the mystery before he tastes anything. If he
has faith and receives it, if there is someone who gives deadly poison to him,
it will not harm him.
Testamentum Domini 2.25: . . . But
always let the faithful take care that, before he eats, he partakes of the
Eucharist, that he may be incapable of receiving injury . . .
In the Hermeneia commentary, we read that
. . . the term “Eucharist” is used
here to denote the consecrated elements themselves rather than as the name for
the whole rite. This is standard practice in early Christianity.
The belief expressed here that the
sacrament has apotropaic power to ward off evil is a clear allusion to Mark
16:18, which says of believers that “if they drink any deadly thing, it will
not hurt them”; but quasi-magical properties were often alleged for the
consecrated elements by early Christian writers. For example, Ignatius describes
the bread of the Eucharist as “the medicine of immortality, the antidote
preventing death” (Eph. 20.2), a phrase that may echo the magical
papyri; Cyprian speaks of the Eucharist as a kind of talisman that protects the
worthy but exposes the guilty (De laps. 26); Cyril of Jerusalem in the
fourth century advises communicants to “sanctify” their eyes by touching them
with the body of Christ that they have just received (Myts. Cat. 5.21);
and Ambrose tells the story of his brother, Satyrus, who when a catechumen
found himself in danger of shipwreck asked Christian fellow passengers to give
him the sacrament which he wrapped in his scarf and then plunged into the deda
(De excessu fratis 1.43). (Ibid., 181)