Matthew 20:22
Jesus answered: you do not know what you are asking. Are you able to drink the cup that I am to drink? They said to him: we are able. The cup that Jesus is about to drink is the cup of suffering — the cup that Gethsemane will reveal in its full intensity (Matthew 26:39). The we are able communicates the disciples' confident but uninformed willingness: they do not yet understand what the cup contains.