The future is hidden by a dark impenetrable veil, and yet we struggle to pierce through it.
- Joseph Barber Lightfoot
You look at a star for two reasons, because it is luminous, and because it is impenetrable. You have beside you a sweeter radiance and a greater mystery, woman.
- Victor Hugo
The Jesuit turned away, saying, sarcastically, "The Protestants are impenetrable rocks." "You are mistaken," said Kutnaur, "it is Christ that is the Rock, and we are firmly fixed upon Him.