The relativity of time and space proves that we live in eternity, and in our life to come this will manifest itself clearly to us:ِ
``In the Resurrection Day, the sinners will swear that they tarried not here except for an hour. But those who are endowed with knowledge and faith will say; verily you have tarried according to Allah's record up to the Resurrection Day which is today, but you were not aware.'' (S 30:55ِ56)
Compared with eternity, our life time in this world is extremely short, and we stay not in this earth except for a little while, if we only could know it.
In the life to come, many things shall be cleared to us; among which is the short probation period that we have to tarry here. The results of our probation and tests and trials, are given to us in the Day of Doom. Now we should know that life is real, earnest, and grave cannot be its goal.