„Lay Participation in the Mystery of Communion‟

While Aquinas acknowledges the historical practice of communion under both kinds in the early Church, he explains why the Western practice developed as it did. He notes that Christ is fully present—body, blood, soul, and divinity—under either form, as St. Paul implies when he writes:

„Whoever eats this bread or drinks the cup of the Lord unworthily will be guilty of profaning the body and blood of the Lord‟ (1 Corinthians 11:27).

Thomas recognizes legitimate reasons why the Eastern tradition maintained communion under both kinds. St. Cyril of Jerusalem taught:

„After having thus become partakers of the Body of Christ, approach also the Cup of His Blood; not stretching forth thine hands, but bending and saying in the way of worship and reverence, ‚Amen,’ be thou hallowed by partaking also of the Blood of Christ.‟

However, Aquinas defends the Western practice as a prudential development that arose from practical concerns: the risk of spilling the Precious Blood, difficulties in administering the chalice to large congregations, and the need to counter certain heresies that denied Christ’s complete presence under either form alone.

Importantly, Thomas does not present this as a matter of dogma but of discipline, which can vary according to the needs of the Church in different times and places. He would point out that the essence of the sacrament is preserved as long as it is celebrated with bread and wine, and both forms are consumed at least by the celebrant.

The Catholic Church has since revised its practice, allowing more frequent reception of communion under both kinds while maintaining that the fullness of Christ is received under either form alone. This development shows the Church’s ability to adapt liturgical practice while preserving essential doctrine.