To read the texts click on the texts: Tobit 3:1-11;Mk 12:18-27
Jesus first corrects their misunderstanding about what the resurrection means and implies. In the resurrection there will no longer be human institutions like marriage and so the question of being given in and taken in marriage does not arise. Humans in the resurrected life will no longer be constrained by the limits or relationships of their earthly bodies. He then uses scripture to establish that resurrection is indeed mentioned in the scripture and is about God’s revelation to Moses in Exodus 3:6-16 as the God of Abraham, Isaac and Jacob and if these are mentioned though they are dead, then he must be the God of the living, since they live in him. God is not God of the dead but the living.
Too much of concern with the after life or heaven and hell may lead to our not living fully this life on earth. Our heaven at this moment is here on earth and we must strive towards making it as enjoyable as possible not only for ourselves but also for those around us.