The Ego And His Own - pg. 141

Properly criticism says: You must liberate your ego from
all limitedness so entirely that it becomes a human ego.
I say: Liberate yourself as far as you can, and you have done
your part; for it is not given to every one to break through all
limits, or, more expressively: not to every one is that a limit
which is a limit for the rest. Consequently, do not tire yourself
with toiling at the limits of others; enough if you tear down
yours. Who has ever succeeded in tearing down even one limit
for all men?