“Having ended the prayers, we salute one another with a kiss.  There is then brought to the president of the brethren bread and a cup of wine mixed with water; and he taking them, gives praise and glory to the Father of the Universe, through the name of the Son and of the Holy Ghost, and offers thanks at considerable length for our being counted worthy to receive these things at His hands.  And when he has concluded the prayers and thanksgivings, all the people present express their assent by saying Amen.  This word Amen answers in the Hebrew language to “so be it.”  And when the president has given thanks, and all the people have expressed their assent, those who are called by us deacons give to each of those present to partake of the bread and wine mixed with water over which the thanksgiving was pronounced, and to those who are absent they carry away a portion.  And this food is called among us the Eucharist, of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined.”

The First Apology of Justin, LXV and LXVI, circa A.­+ D. 155