Very few people ask honest open questions.  The quest for learning with an unprejudiced mind is rare.  Scientists start with an idea which they try to prove through experiments.   A cross examining barrister in Court will assume where the truth lies and then ask questions to prove it.  Questions are usually designed to verify what has been assumed a point; so those with an axe to grind ask questions that will vindicate themselves and condemn their opponents.  

Until this point in Mark's Gospel, the religious Pharisees had been in the spotlight.  They believed in a resurrection but they were legalists … wrongly believing that if you did enough that was right then God would welcome you into His heaven.  But now Mark takes us behind the scenes of the Sadducee mind.  They were liberal sacramentalists who did not believe in any resurrection, heaven or hell or moral accountability.  They claimed to only keep to the written Torah but easily absorbed Greek philosophy and conformed to the Roman occupation in order to gain positions of power and wealth.  For the Sadducees, the life you saw was the whole story: no after-life for them.  

Their question was designed to trap Jesus.  They postured the scenario of a widow who was married to her late husband's brother according to the Mosaic law of Levirate marriage (Deuteronomy 25:5-10).  The principle being that the brother would give the widow children, who would inherit the dead brother's land and provide for the widow in her old age.  Taking the principle to absurdity, they suggested that all seven brothers died in sequence having married the woman.  They then posed the question to mock the idea of an after-life, supposing that there is a resurrection, of whose wife would the widow be?  Why did they ask this question?  Had they heard Jesus say He would rise again?  Were they competing with the Pharisees?  They were trying to trap Jesus because His purity disturbed their consciences.  

Modern Pharisees and Sadducees can be found in churches today.  It is not trying to be good or a thirst for knowledge that brings us to God - Paul describes such people as 'always learning but never able to come to the knowledge of the truth' (2 Timothy 3:7).  We need a thirst for purity and righteousness (Matthew 5:6).  Unless our starting point is informed by God's Word, there is little hope of arriving at His truth.  And that was the point Jesus was going to make (Mark 12:24).  It is the same with our friends: discussion about God can only reach the truth if it starts with His revelation.  That is why it is important to tell out what God's Word says - they will never know otherwise!  However many questions and comments may transit a coffee table, the truth will only emerge when we start with what God says!  That is our daily challenge.