Quote from ACIM Text Chapter 4, Section 1 - Introduction.

The Bible says that you should go with a brother twice as far as he asks. It certainly does not suggest that you set him back on his journey. Devotion to a brother cannot set you back either. It can lead only to mutual progress. The result of genuine devotion is inspiration, a word which properly understood is the opposite of fatigue. To be fatigued is to be dis-spirited, but to be inspired is to be in the spirit. To be egocentric is to be dis-spirited, but to be self-centered in the right sense is to be inspired or in spirit. The truly inspired are enlightened and cannot abide in darkness.