Charles Ellicott Commentary Matthew 26:27

"And he took a cup, and gave thanks, and gave to them, saying, Drink ye all of it;" — Matthew 26:27 (ASV)

He took the cup, and gave thanks — The better manuscripts omit the article, thus making it, “a cup.” In the later ritual of the Passover, the cup of wine (or rather, of wine mixed with water) was passed around three times during the supper. One such cup had been passed around early in the evening (Luke 22:17); now another becomes, under a solemn consecration, the symbol of a diviner truth than had yet been revealed to the listening and wondering disciples.