Six at the top means:

Pushing upward in darkness.
It furthers one
To be unremittingly persevering.

He who pushes upward blindly deludes himself. He knows only advance, not retreat. But this means exhaustion. In such a case it is important to be constantly mindful that one must be conscientious and consistent and must remain so. Only thus does one become free of blind impulse, which is always harmful.