These are the lips of the lake, on which no beard grows.
"I can't imagine you with a beard," she finally said.
In his eyes the beard was a symbol of the old regime, and as such it must be removed.
On the importance attached to the beard, see Ency.
Their opinion and practice will be best represented in the words of one of their early teachers (quoted by Gibbon, Decline and Fall, c. 63): "When thou art alone in thy cell shut thy door, and seat thyself in a corner; raise thy mind above all things vain and transitory; recline thy beard and chin on thy breast; turn thine eyes and thy thought towards the middle of thy belly, the region of the navel (6j4 aXos); and search the place of the heart, the seat of the soul.