As the refreshment of the body is wrought by means of meat and drink, so under the form of meat and drink the Lord has provided for us spiritual refreshment. And it was suitable that for the shewing forth the Lord’s Passion this Sacrament should be instituted under both kinds.
For in His Passion He shed His Blood, and so His Blood was separated from His Body. It behoved therefore, that for representation of His Passion, bread and wine should be separately set forth, which are the Sacrament of the Body and Blood. But it should be known, that under both kinds the whole of Christ is contained; under the bread is contained the Blood, together with the Body; under the wine, the Body together With the Blood.
Ambrosiaster, in 1 Cor 11:26 : And for this reason also in do we celebrate under both kinds, because that which we receive avails for the preservation of both body and soul.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: non occ.