1 Corinthians 11:4

Verse 4. Praying or prophesying. By prophesying, in this place is meant, reading publicly in the Church, or singing, or explaining some part of the Scripture. To have the head covered, or uncovered, is in itself a thing very indifferent. Amongst the Greeks it was the custom always to sacrifice to their idols with heads uncovered; amongst the Romans, the opposite was the fashion, and among the Jews, as well formerly as at present, they always appear in their synagogues with heads covered. Calmet.