St. Nicholas Cabasilas 1323-1391
The Holy Spirit grants to those who partake of the sacred offerings the remission of sins of their sins. “Let not this grace be removed from these offerings because of my sins.” There are two ways in which grace operates in the precious offerings; first, by grace they are sanctified, and secondly, by grace we are sanctified through them.
The working of grace upon the offerings — the first of which we spoke — cannot be invalidated by any human evil. Since the consecration of the offerings is not the work of human virtue, it cannot be hindered in any way by the wickedness of men.
But the second, the working of grace within us, demands our co-operation, and as a result, our negligence can impede it. In other words, grace will sanctify us through the sacred offerings if it finds us ready and fit for sanctification; if it should, on the other hand, find us unprepared, not only do we reap no benefit, but we suffer grave harm and loss. (A Commentary on the Divine Liturgy, 34)