Philo Judaeus De Vita Contemplativa 66

[66] Therefore when they come together clothed in white garments, and joyful with the most exceeding gravity, when some one of the ephemereutae (for that is the appellation which they are accustomed to give to those who are employed in such ministrations), before they sit down to meat standing in order in a row, and raising their eyes and their hands to heaven, the one because they have learnt to fix their attention on what is worth looking at, and the other because they are free from the reproach of all impure gain, being never polluted under any pretence whatever by any description of criminality which can arise from any means taken to procure advantage, they pray to God that the entertainment may be acceptable, and welcome, and pleasing;