You will notice that, during the Holy Sacrifice of the Mass, while the choir chants the Agnus Dei, the priest will break the Host into three pieces. Two parts are left upon the paten, while one part (which is very small) is placed into the chalice of the Precious Blood. This is called the rite of “commingling”, because it is at this point that the Body and Blood of Christ are sacramentally mingled together – though the Lord is fully present in both the Host and the chalice, the one is the Sacrament of his Body and the other is the Sacrament of his Blood.
As the priest performs this rite he prays: “May this mingling of the Body and Blood of our Lord Jesus Christ bring eternal life to us who receive it.” There is, in the very rite itself, a direct connection between the commingling and salvation! St. Thomas Aquinas, following an ancient tradition, has shown how the whole Church is mystically present in this sacramental rite. Here, hidden in the rite of the Mass, we find a symbol of our two feast days – All Saints’ and All Souls’.