Paradise Lost, Book 5.
I do not think my sister …
… So unprincipled in Virtue's book
And the sweet peace that goodness bosoms ever,
As that single want of light and noise
Could stir the constant mood of her calm thoughts,
And put them into misbecoming plight.
Virtue could see to do what Virtue would
By her own radiant light, though sun and moon
Were in the flat sea sunk. And Wisdom's self