it is
acquired by its subject successively, such as health; and therefore
because a substantial form does not receive more and less, it follows
that its introduction into matter is instantaneous.

Secondly on the part of the subject, which sometimes is prepared
successively for receiving the form; thus water is heated
successively. When, however, the subject itself is in the ultimate
disposition for receiving the form, it receives it suddenly, as a
transparent body is illuminated suddenly. Thirdly on the part of the
agent, which possesses infinite power: wherefore it can instantly
dispose the matter for the form. Thus it is written (Mk. 7:34) that
when Christ had said, "'Ephpheta,' which is 'Be thou opened,'
immediately his ears were opened, and the string of his tongue was
loosed."

For these three reasons this conversion is instantaneous. First,
because the substance of Christ's body which is the term of this
conversion, does not receive more or less. Secondly, because in this
conversion there is no subject to be disposed successively. Thirdly,
because it is effected by God's infinite power.

Reply Obj. 1: Some [*Cf. Albert the Great, Sent. iv, D, 11; St.
Bonaventure, Sent., iv, D, 11] do not grant simply that there is a
mid-time between every two instants. For they say that this is true
of two instants referring to the same movement, but not if they refer
to different things. Hence between the instant that marks the close
of rest, and another which marks the beginning of movement, there is
no mid-time. But in this they are mistaken, because the unity of time
and of instant, or even their plurality, is not taken according to
movements of any sort, but according to the first movement of the
heavens, which is the measure of all movement and rest.

Accordingly others grant this of the time which measures movement
depending on the movement of the heavens. But there are some
movements which are not dependent on the movement of the heavens, nor
measured by it, as was said in the First Part (Q. 53, A. 3)
concerning the movements of the angels. Hence between two instants
responding to those movements there is no mid-time. But this is not
to the point, because although the change in question has no relation
of itself to the movement of the heavens, still it follows the
pronouncing of the words, which (pronouncing) must necessarily be
measured by the movement of the heavens. And therefore there must of
necessity be a mid