of Christ could increase.

_On the contrary,_ It is written (John 1:14): "We saw Him [Vulg.:
'His glory'] as it were . . . the Only-begotten of the Father, full
of grace and truth." But nothing can be or can be thought greater
than that anyone should be the Only-begotten of the Father. Therefore
no greater grace can be or can be thought than that of which Christ
was full.

_I answer that,_ For a form to be incapable of increase happens in
two ways: First on the part of the subject; secondly, on the part of
the form itself. On the part of the subject, indeed, when the subject
reaches the utmost limit wherein it partakes of this form, after its
own manner, e.g. if we say that air cannot increase in heat, when it
has reached the utmost limit of heat which can exist in the nature of
air, although there may be greater heat in actual existence, viz. the
heat of fire. But on the part of the form, the possibility of
increase is excluded when a subject reaches the utmost perfection
which this form can have by nature, e.g. if we say the heat of fire
cannot be increased because there cannot be a more perfect grade of
heat than that to which fire attains. Now the proper measure of
grace, like that of other forms, is determined by the Divine wisdom,
according to Wis. 11:21: "Thou hast ordered all things in number,
weight and measure." And it is with reference to its end that a
measure is set to every form, as there is no greater gravity than
that of the earth, because there is no lower place than that of the
earth. Now the end of grace is the union of the rational creature
with God. But there can neither be nor be thought a greater union of
the rational creature with God than that which is in the Person. And
hence the grace of Christ reached the highest measure of grace. Hence
it is clear that the grace of Christ cannot be increased on the part
of grace. But neither can it be increased on the part of the subject,
since Christ as man was a true and full comprehensor from the first
instant of His conception. Hence there could have been no increase of
grace in Him, as there could be none in the rest of the blessed,
whose grace could not increase, seeing that they have reached their
last end. But as regards men who are wholly wayfarers, their grace
can be increased not merely on the part of the form, since they have
not attained the highest degree of grace, but also on the part of the
subject, since they have not yet attained their en