Luke 20:31-36

Luke 20:31 (KJB)
And the third took her; and in like manner the seven also: and they left no children, and died.

So the Sadducee continues until he finally exhausts the entire line of brethren down to the seventh son.

Luke 20:32 (KJB)
Last of all the woman died also.

Finally after seven husbands, the woman died also leaving no children.

Luke 20:33 (KJB)
Therefore in the resurrection whose wife of them is she? for seven had her to wife.

Here they thought that they would have Jesus because if seven husbands had her, then which one of the seven husbands could lay claim to her after they are all resurrected? They had assumed that the seven would be in constant argument about who had the right to her. These Sadducees like the Pharisees, whenever they put together a scenario where they would try and trap Jesus, found out that they were the ones who were always trapped because they did not know they were dealing with deity.

Luke 20:34 (KJB)
And Jesus answering said unto them, The children of this world marry, and are given in marriage:

Then Jesus explains to them that the normal order of life in this world is that one will marry and the other is given in marriage. This was done for the purpose of procreation and to build the family which is the backbone of society. The Sadducees did not believe in the life to come but they knew what the beliefs were of the other Jewish systems such as the Pharisees who believed in the resurrection. So Jesus contrasts what happens in this world under the present natural order with what happens in the next life and the differences thereof.

Luke 20:35 (KJB)
But they which shall be accounted worthy to obtain that world, and the resurrection from the dead, neither marry, nor are given in marriage:

Jesus speaks of those who shall be accounted worthy to obtain that world and the resurrection. The ones who will attain to these are those who are in Christ. Those who have become born again in this world. Jesus is basically telling them that not everyone is going to make it to Heaven but there will only be a certain amount of people who will be counted worthy. To be accounted worthy, one must have all their sins removed in this life because no sinful soul can ever enter into Heaven because it is a place of pure righteousness. (Mat 5:20 KJV) For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven. The only way for one to exceed the righteousness of the scribes and Pharisees is to be born again in Christ. Then Jesus states that in Heaven, they will neither marry or be given in marriage because no longer will there be any reason to procreate since all the Elect will have been saved plus there is going to be a new order of existence for the true believers in the New Heaven and New Earth.

Luke 20:36 (KJB)
Neither can they die any more: for they are equal unto the angels; and are the children of God, being the children of the resurrection.

(1 Cor 15:44 KJV) It is sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body. There will be a great difference between the natural body that is placed in the grave and the spiritual body which will be resurrected. Since death will be no more, then marriage for the purpose of procreation will no longer be necessary. The resurrected body will be like that of the angels which are a spiritual body. It is interesting that Jesus is likening the resurrected body to the angels, something which the Sadducees do not believe in. The principle is thus, just because someone believes a certain way or does not believe a certain way, has no effect on the truth. The Rabbis had taught that the world to come will be a continuation of the present one, but without evil or death. Jesus is trumping their belief by telling them that the world to come is going to be one of a higher order which will replace this present world. (Rev 21:1 KJV) And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea.