Such an uninterrupted intention will not be actual but virtual; that is to say, once made, it will continue to motive conduct without further express advertence, as the consideration of wages motives a workman's toil. From intention St Thomas distinguishes attention. Actual attention can no more be continous than actual intention; and attention is nothing, if it is not actual; there is no virtual attention. Thus in no way can attention to God be continuous under ordinary conditions of humanity. We have to be satisfied with the virtual continuity of our intention to please God.

Of God and His Creatures: 3.130