"Verily I say unto you, this generation shall not pass, till all these things be fulfilled. Heaven and earth shall pass away, but my words shall not pass away. MATTHEW XXIV.34,35.
THIS text has, in my opinion, been more abused than any other text in the whole word of God. It has been misunderstood, and perverted to support doctrines diametrically opposite to many of the most important truths revealed in the holy Scriptures. 
On the one hand, it has been used to prevent many from believing in the future coming of Jesus Christ; and others have made it a pillar for the sentiment of universal salvation;
The word "fulfil" signifies to perform, accomplish, complete, or finish. This is the primary meaning of the word. And it is evident that our Savior had this meaning;
The strict and literal meaning of the word generation is, children of one common parent, and is applied to many things, such as classes of like nature, or sprouts from the same root; cattle from the same stock; the human race from the same common parent; all men living at a certain age, being the children of that age; children of one family, because they were all from one parent; children of God.....Also, the Jews are called a generation, because they are the children of Abraham. The wicked are called a generation, because they are the children of the devil..... Christ to mean, by "generation," the race of Adam: the human family will not pass off the earth until Christ comes in the clouds.
Q: WHAT IS THE MEANING OF "HEAVEN AND EARTH PASSING AWAY."?
Peter, in showing the consummation of the present heavens and earth, has taught us how to reason in this case. 2Pet.iii.5: For this they willingly are ignorant of, that by the word of God the heavens were of old, and the earth standing out of the water and in the water.
Q: Who are ignorant?
A: The scoffers.
Q: Why are they ignorant?
A: Because they are willingly so.
But the heavens and the earth which are now. - showing that there had been heavens and an earth before, - by the same word are kept in store, - by the same power, and in a similar manner, kept, - reserved unto fire against the day of judgment and perdition of ungodly men." vs.7.
Q: How is it possible that false teachers can deceive
people who have a Bible, and can read?
people who have a Bible, and can read?
If we will be ignorant, notwithstanding the plainness and simplicity of God's word, then, if we perish, our blood will be upon our own heads.
The passing away of the heavens and earth, then, is to be by fire, as it was by water. As it was in the days of Noah, so shall it be in the days of the Son of man."
William Miller