The last two lines;
We are farther from perfection,
But closer to him.
Are just saying since Adam and Eve were so long ago and they were created to be perfect, and then they sinned so they were no longer perfect, but closer than any over human ever were but with every generation they(we, us) got less perfect
But it's also saying that our generation has a better chance of the second coming of Jesus Christ so were closer to seeing him also