Matthew 26:27

The cup] RV 'a cup.' Since it was taken after supper (St. Luke and St. Paul), and is expressly called by the latter the 'cup of blessing' (1 Corinthians 10:16), it was clearly the third cup of the paschal supper, called by the rabbis the 'cup of blessing' (No. 9). The ritual was as follows: (1) It was washed and cleansed; (2) the wine in it was mingled with water, and it was blessed; (3) it was crowned, i.e. the worshippers stood round it in a ring; (4) the householder veiled his head and sat down; (5) he drank it, holding it with both hands.

That the cup of the Christian sacrament was also mingled with water, was indicated by Jesus Himself, when He called it 'this fruit of the vine.' The Talmud says, 'The rabbis have a tradition. Over wine which hath not water mingled wiih it they do not say the blessing, “Blessed be He that created the fruit of the vine,” but, “Blessed be He that created the fruit of the tree.” 'And it is added, 'The wise agree with Rabbi Eleazar, that one ought not to bless over the cup of blessing till water be mingled with it.'