The Sadducees must have found Jesus very threatening.  He challenged their conservative religious beliefs; he challenged their 'empty', formal kind of religion; he may have also challenged their security and life-style.  They may have been  worried that he might raise up a rebellion against the Romans and threaten their security.  They wanted to find a way to trip him up.

They were not much different from us.  Most of us don't like our comfortable religion to be challenged and we will resist new thoughts and ideas.

(Note:  I'm not suggesting that every 'formal' style of worship is 'empty'. Christians have developed many different styles of worship and all can be very meaningful in different ways. When I was a child I was a 'lonely only' and accepted any invitation I got to visit other families for meals or sleep-overs.  I enjoyed being part of a larger family.  I was fascinated to notice that in every home I visited, the meal tables were set in different ways.  But the food was always good!  I relate this to the different liturgies and ways of worshipping in different churches: the ritual may be different, but the spiritual 'food' is nourishing.  The 'religion' of the Sadducees, it seems, did not provide spiritual nourishment; there was a table set, but no 'food'!)

V 28 - 33
Their question was this: 'Master, Moses laid it down for us that if there are brothers, and one dies leaving a wife but no child, then the next should marry the widow and carry on his brother's family. Now, there were seven brothers: the first took a wife and died childless; then the second married her, then the third. In this way the seven of them died leaving no children. Afterwards the woman also died. At the resurrection whose wife is she to be, since all seven had married her?

The Sadducees addressed Jesus as Master, or Teacher(NIV, NLT, TEV), even though they did not accept his authority.  Their question was not about a genuine concern.  They wanted to trip Jesus up.  They quoted the part of the scriptures they believed in and made up a hypothetical story to try to ridicule the things that Jesus was teaching. They trotted out what was probably a well-used argument about the issue of resurrection.

When we are discussing contoversial issues, it's very easy to trot out the same old Bible verses and passages that support our own point of view, as the Sadducees did here, rather than search through the Bible to find out as much as we can about what it says about an issue in all areas relating to it.  It is important that we listen carefuly to other points of view and check them out thoroughly.  It's just possible we might not be right!!!! <Shock! Horror!!>

Quest Study Bible note, p 1366.  By Jewish law, a man was supposed to marry his brother's widow, providing for her and raising their firstborn son in his brother's name.

Deuteronomy 25: 5, 6. (NIV)  If brothers are living together and one of them dies without a son, his widow must not marry outside the family.  Her husband's brother shall take her and marry her and fulfill the duty of a brother-in-law to her.  The first son she bears shall carry on the name of the dead brother so that his name will not be blotted out from Israel.

Quest Study Bible note. p 267. A man was required to marry his brother's widow unless she had already borne a son.  This preserved the deceased man's name and kept his property within the family.  It also served as a social security system, providing the widow a means of support.   If a man refused to carry out this duty, the widow could bring him to trial before the town elders.  If he still refused, then another male relative could assume the responsibility (as happened in the story of Ruth and Boaz - Ruth 4: 1-12)

New Bible Commentary, p 1012.  The Sadducees' story was designed to show the absurdity of the resurrection in the light of 'levirite marriage'.  This was based on the principle that if a husband died, his brother should marry the widow in order to raise up a male heir for him.  Theoretically a woman might have several husbands in turn; so did not this make the idea of resurrection a nonsense?

V 34- 36
Jesus said to them, 'The men and women of this world marry; but those who have been judged worthy of a place in the other world and of the resurrection from the dead, do not marry, for they are not subject to death any longer. They are like angels; they are sons of God, because they share in the resurrection.
NLT.  Jesus replied, "Marriage is for people here on earth.  But that is not the way it will be in the age to come.  For those worthy of being raised from the dead won't be married then.  And they will never die.  In these respects they are like angels.  They are children of God raised up to new life.

In his reply, Jesus pointed out to the Sadducees that marriage is an institution meant just for this life, given for specific 'earth-bound' reasons of bringing children into being, companionship and mutual support.  Once this physical life is over, we don't need marriage as we won't need to produce more children and we'll have the closeness of many others and of our heavenly father in a relationship that we can only begin to guess about in this life.

New Bible Commentary, p. 1012.. Jesus stated that conditions in the resurrection are not like those on earth.  Since there is no death and hence no need to replenish the race, there is no need for procreation .... More probably  all human relationships are lifted up to such a high level in heaven that the exclusiveness of marriage will not be a factor in heaven as it is on earth.

V 37.
That the dead are raised to life again is shown by Moses himself in the story of the burning bush, when he calls the Lord, "the God of Abraham, Isaac and Jacob".
NLT.  But now, as to whether the dead will be raised - even Moses proved this when he wrote about the burning bush.  Long after Abraham, Isaac, and Jacob had died, he referred to the Lord as 'the God of Abraham, the God of Isaac, and the God of Jacob'.
 
Jesus' argument about whether the dead are 'dead' for ever or raised to a new life was that Moses called God the God of Abraham, Isaac and Jacob - who were already long dead when Moses lived.  He implied that if they were really dead, in the sense of no longer existing, how could Moses say God was still their God?  He quoted the person they accepted as an authority to prove his point.

New Bible Commentary, p 1012.  Jesus gave an argument for the resurrection based on the law of Moses.  At the burning bush God had said:? 'I - the God of Abraham' (Exodus 3:6).  In a Hebrew sentence of this kind, there was no verb expressed, and Jesus was implying that the present form of the verb 'I am' must be supplied (as in the Greek translation of the Old Testament), showing that God still said that he was the God of Abraham centuries after his death - with the implication that Abraham was still alive and able to worship him.  The God who was Abraham's God during his lifetime would not let death interrupt the relationship but would resurrect him.

V 38.
God is not God of the dead but of the living; for him all are alive.'
TEV.  This means that he is the God of the living, not of the dead - for all are alive to him.

If God is the God of those who are alive, and he calls himself the God of Abraham and others who have died, then, logically, he must consider that they are alive, not dead; they must be resurrected.  So, according to Jesus' argument, the resurrection is a fact of life!

When and how we will be resurrected is another question - and we may have to wait till it happens before we can know for sure exactly what it all means.  Here is another matter we just have to trust God about and accept without being able to fully understand.