Albert Barnes 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)

And he took the cup. That is, the cup of wine which they used at the feast of the Passover, called the cup of Hallel, or praise, because they then began repeating the psalms with which they closed the Passover. See Matthew 26:30.

This cup, Luke says, he took after supper. That is, after they had finished the ordinary celebration of eating the Passover. The bread was taken while they were eating, and the cup after they had finished eating.

And gave thanks. See Barnes, "Matthew 26:26".

Drink you all of it. That is, "all of you, disciples, drink of it;" not, "drink all the wine."