Michaelmas

An angel's power and nature are finite, whereas the Divine power and essence, which is the universal cause of all things, is infinite: consequently God through His power touches all things, and is not merely present in some places, but is everywhere. Now since the angel's power is finite, it does not extend to all things, but to one determined thing. For whatever is compared with one power must be compared therewith as one determined thing. Consequently since all being is compared as one thing to God's universal power, so is one particular being compared as one with the angelic power. Hence, since the angel is in a place by the application of his power to the place, it follows that he is not everywhere, nor in several places, but in only one place.

— Saint Thomas Aquinas, Summa Theologica, Prima Pars, Question 52, Article 2: Whether an angel can be in several places at once?