At the same time, we must tell them openly and frankly that a state of mind is by itself insufficient for leadership of the masses in a great revolutionary struggle, and that the cause of the revolution may well be harmed by certain errors that people who are most devoted to the cause of the revolution are about to commit, or are committing.

Make this lower case.
at the same time, we must tell them openly and frankly that a state of mind is by itself insufficient for leadership of the masses in a great revolutionary struggle, and that the cause of the revolution may well be harmed by certain errors that people who are most devoted to the cause of the revolution are about to commit, or are committing.