How can I be pure in Spirit?

Look at the sun for a second or two when shining in its strength, undimmed by clouds, and what is the effect on the eye? 

Darkness.

Continue to gaze on the great luminary and blindness ensues. 

And such would be the result were you permitted to cast but one glance on Pure Spirit—

It is so intensely, grandly bright.

It is too divine for our bodily eyes—

We require eyes of another kind to look on it with safety.