St. Thoma claims eternity contains all time, and that the eternal point of view is like one watching from a high perch what a temporal thing sees only at the ground level. Thus time is compared to spacial extension and the motion through it. I think something like these comparisons and metaphors is unavoidable in an account of eternity, but there is a problem in the image that is important to address: In setting all time out in front of the eternal being, we lose exactly the element that makes it time, for it loses any flow or passing.
What do we mean when we say that the eternal being knows the whole of time? And why do we make this knowledge an “eternal present”? All “present” means here is that the eternal being knows the whole of time when he knows it, though the “when” is not a moment in time; we anticipate the future, remember the past, and see the present by “direct intuition”, and since the eternal being knows by a direct intuition, we say whatever he knows is “present”. But the analogy obscures the reality and gives one the misguided impression that the whole of time becomes present, which is simply a contradiction. Even if we make the whole of time composed of “presents”, this present existence is always bounded between the contingency of the future and the necessity of the past: and so to see time as a whole means to see it not only according to its present character but according to its contingent and necessary character. The divine containment of all time must ground both the necessity of the past and the contingency of the future, and it has to do so at each and every point of present existence. The procession of the temporal universe from the divine act of creation is not a line made up of infinite present points (again, another contradiction) but rather time in its future contingency and past necessity along with the present moment that serves as a limit between them. This does not require that any one moment be “the” present any more than having five apples requires any one of them be the fifth one. Which one is the fifth is only materially significant since any one can be the fifth in relation to the others.
Briefly, eternity requires us to consider time as a whole, but imagination will distort this into an error if we take this as making time a single, motionless block given in the way that the parts of a magnitude are given. The present can be taken as a limit, but it is not a limit of a homogeneous magnitude, but rather of the ontologically heterogeneous past (necessary) and future (contingent).