isn't this only problematic because of the way in which we are bound by the law of time? I am thinking of an amazing sermon I heard by the abbot of _____ some months ago on the passage you just mentioned:

Mat 22:31 But as touching the resurrection of the dead, have ye not read that which was spoken unto you by God, saying,
Mat 22:32 I am the God of Abraham, and the God of Isaac, and the God of Jacob? God is not the God of the dead, but of the living.

He started off by talking about recent geological finds near the abbey. [a footprint many millions of years old or some such] and went on to talk about how God sees and dwells outside of time and that we are offered a share in that life.
which means, if I understand this aright, that we are living already in the eternity of God ("the kingdom of God is at hand") but can only glimpse this reality by his grace 'as in a glass darkly'.
I am thinking here also of the strange way in which the Old Testament speaks often (especially in the psalms) in a future tense when it really seems to mean the 'now'. FUTURE and NOW are, in a terrifyingly simple way, the Same Thing as I have begun to discover when, over and over,I hear myself saying 'manyana, manyana' but manyana never comes until I make it happen in the NOW . . . .
I heard the dalai lama talking about his spiritual practices and repeating over and again with some urgency: "time is short and so all the more need to practice, practice, practice!" (He means practising his meditation and his holy work of course). Jesus too emphasizes the urgency to prayer over and over . . . . I am thinking particularly here of the garden of gethsemane where Jesus gets really upset that the disciples cannot watch with him for even an hour without dozing off. . .
so the past is where we cannot act and the future is where we cannot act. The only place that we can act is in the NOW and it is only in the NOW that we can meet God . . . .
Just one further thought on this: modern man has developed a tendency to mourn what has passed. Many of us (and certainly society as a generalised whole) suffers from constant nostalgia - heartfelt hankering after a 'golden bygone age'. It colours the way in which we see childhood and the way in which we see history and our own lives too. Not only does this prevent us from living in the present (where God dwells) but it also makes us more fearful of the future. I am convinced that there is a connection between my own deeply flawed understanding of time and my need for discipline and constant prayer to help me to stay living with God in the eternal Present . . .
and again, (all roads lead to Rome) this ties in with my understanding of my love of boys as a looking back to things that I wished I had had (and sometimes think that I almost did) . . . .