St. Thomas Aquinas
“Greater devotion is required in this sacrament [Eucharist] than in the others, for the reason that the entire Christ is contained therein. Moreover, this sacrament requires a more general devotion, i.e. on the part of the whole people, since for them it is offered; and not merely on the part of the recipients, as in the other sacraments.”
Source: St. Thomas Aquinas, Summa Theologica