Here's how I would define Christian success.
Then the King will say to those at his right hand, `Come, O blessed of my Father, inherit the kingdom prepared for you from the foundation of the world; for I was hungry and you gave me food, I was thirsty and you gave me drink, I was a stranger and you welcomed me, I was naked and you clothed me, I was sick and you visited me, I was in prison and you came to me.' Then the righteous will answer him, `Lord, when did we see thee hungry and feed thee, or thirsty and give thee drink? And when did we see thee a stranger and welcome thee, or naked and clothe thee? And when did we see thee sick or in prison and visit thee?' And the King will answer them, `Truly, I say to you, as you did it to one of the least of these my brethren, you did it to me.'
Then he will say to those at his left hand, `Depart from me, you cursed, into the eternal fire prepared for the devil and his angels; for I was hungry and you gave me no food, I was thirsty and you gave me no drink, I was a stranger and you did not welcome me, naked and you did not clothe me, sick and in prison and you did not visit me.' Then they also will answer, `Lord, when did we see thee hungry or thirsty or a stranger or naked or sick or in prison, and did not minister to thee?' Then he will answer them, `Truly, I say to you, as you did it not to one of the least of these, you did it not to me.' And they will go away into eternal punishment, but the righteous into eternal life.
It's not about how many members you have. It's not about how many Kingdom Halls you build. It's about the WORKS OF MERCY helping the people of 'the world' Witnesses pride themselves in shunning.
When was the last time you recall Witnesses gathered to volunteer at a soup kitchen or provide aid after a natural disaster? I guarantee you the next time will be the first time. Yet you boast about the number of converts while people, some of them even your own, go hungry.
Please reread those verses and think about the real fruits of being 'no part of this world'.