On page 15, Abbot Vonier quotes the O sacrum convivium [which happens to be indulgenced]:

O sacred Banquet, wherein Christ is received, the memory of His passion is recalled, the soul is filled with grace, and there is given to us a pledge of future glory.

We are (or should be) used to the idea of the Eucharist as a "re-presentation" of Christ's sacrifice on Calvary, that it makes present in our churches the one sacrifice offered once and for all outside Jerusalem nearly two millennia ago. We understand, indeed many of us can testify, that receiving the Eucharist confers graces upon the receiver. We might even occasionally think of the future glory pledged by the Eucharist -- the Body, Blood, Soul, and Divinity of Jesus Christ, Who is now seated at the right hand of the Father.

But Abbot Vonier quotes this prayer in the context of discussing how, as he writes a page before, every sacrament

recalls the past, it is the voice of the present, it reveals the future.

A sacrament can do these things because it is a sign.

Being a sign of something else might be thought of as an imperfection, as though what really counts is the thing signified and the sign itself is ephemeral, passing from the mind as soon as what is signified is recognized. This isn't the case with a sacrament, though; the fact that it is a sign is what makes it capable of containing the past, the present, and the future all at once.

As St. Thomas writes (and Abbott Vonier quotes), when discussing whether a sacrament is a sign of one thing only:

...a sacrament properly speaking is that which is ordained to signify our sanctification. In which three things may be considered; viz.

• the very cause of our sanctification, which is Christ's passion;
• the form of our sanctification, which is grace and the virtues;
• and the ultimate end of our sanctification, which is eternal life.

As I suggested, thinking of the Eucharist in these terms comes more or less readily to Catholics. Baptism, too, if we are aware that we who were baptized into Christ Jesus were baptized into His death, and that if we have grown into union with Him through a death like His, we shall also be united with Him in the resurrection.

But what about the other sacraments? Do we ever think about how marriage recalls the past, or holy orders reveals the future?

I know that I tend to collapse the idea of a sacrament into an outward sign of an inward grace given by the sacrament. That's certainly true, but it's inadequate. If the graces received are all there is to it, then what's the point of the sign? To tell us particular graces are being received? Then why not just pray for those particular graces and skip all the fuss with the oil and the water and so forth?

Because, as Abbot Vonier explains, you need a sign if you want to tie the past, present, and future all together, and

to limit the sacramental power of signification to the present moment, to the transformation of soul which takes place when the sacrament is received, would be an unwarranted minimizing of the sacramental doctrine, and would leave much of our scriptural language unintelligible. (p. 16)