How long is eternity?

               I read a story somewhere to explain the unmeasurable time period of eternity.There is a Land in a far away North called Svithjod.There stands a mighty rock which is few hundred miles high and few hundred miles wide.Once in a every thousand years a little bird came up there  to sharpen its beak.When the rock worn away(due to the sharpening of its beak!)then a single day of eternity will have gone by.
            seems like its not going to end.Are we ready to live a eternal life with Jesus?If we could not lead a pure life for atleast 60-70 years in this world remember how could we live there with a pure mind and soul eternally?
          No one with a dirty mind(rarely,occasionally,sometimes,often- these words doesn't work with God.)can enter the kingdom of God.Our Living God doesn't change today tomorrow and forever and in eternity there is no grace period to fall back in sin and crying bucket of tears for forgiveness.There is no angel standing in front of the Gate to Heaven spreading a magical wand around your(our) head and make us pure in soul instantly.Purity is something we must practice in this world.If we live with Jesus here in our Life span (i.e)60-70 years,he will be ready to live with us there in his Life span (i.e) Eternity.Afflictions we face in this earth is not equal to the glory we will obtain in Heaven. In Revelation 22:11,12 Bible says

"Let the one who does wrong, still do wrong; and the one who is filthy, still be filthy; and let the one who is righteous, still practice righteousness; and the one who is holy, still keep himself holy."

"Behold, I am coming quickly, and My reward is with Me, to render to every man according to what he has done".

Amen,Come Lord Jesus