Pieter Bruegel the Elder, The Parable of the Blind, 1568, distemper on linen canvas, 86 cm × 154 cm (34 in × 61 in), Museo di Capodimonte, Naples, Italy.
But he answering them, said: Every plant which my heavenly Father hath not planted, shall be rooted up. Let them alone: they are blind, and leaders of the blind. And if the blind lead the blind, both will fall into the pit.
Matthew's Gospel, ch. 15 (13-14)