"The blind leading the blind" is a metaphor

Metaphor

A metaphor is a literary figure of speech that uses an image, story or tangible thing to represent a less tangible thing or some intangible quality or idea; e.g., "Her eyes were glistening jewels." Metaphor may also be used for any rhetorical figures of speech that achieve their effects via...

 used in antiquity, notably by Jesus

Jesus

Jesus of Nazareth , commonly referred to as Jesus Christ or simply as Jesus or Christ, is the central figure of Christianity...

 in the Matthew

Gospel of Matthew

The Gospel According to Matthew is one of the four canonical gospels, one of the three synoptic gospels, and the first book of the New Testament. It tells of the life, ministry, death, and resurrection of Jesus of Nazareth...

  and Luke

Gospel of Luke

The Gospel According to Luke , commonly shortened to the Gospel of Luke or simply Luke, is the third and longest of the four canonical Gospels. This synoptic gospel is an account of the life and ministry of Jesus of Nazareth. It details his story from the events of his birth to his Ascension.The...

 , as well as in the non-canonical Gospel of Thomas

Gospel of Thomas

The Gospel According to Thomas, commonly shortened to the Gospel of Thomas, is a well preserved early Christian, non-canonical sayings-gospel discovered near Nag Hammadi, Egypt, in December 1945, in one of a group of books known as the Nag Hammadi library...

 (Saying 34).

In Matthew, Jesus responds to a question about the Pharisees

Pharisees

The Pharisees were at various times a political party, a social movement, and a school of thought among Jews during the Second Temple period beginning under the Hasmonean dynasty in the wake of...

 saying:
The use in Luke has a different context:
A number of illustrations of the New Testament

New Testament

The New Testament is the second major division of the Christian biblical canon, the first such division being the much longer Old Testament....

 metaphor exist, the most famous being The Blind Leading the Blind

The Blind Leading the Blind

The Blind Leading the Blind is an oil painting by Pieter Bruegel the Elder, dating from 1568 and housed in the Capodimonte Museum, Naples, southern Italy. Other titles include Blind and The Parable of the Blind....

by Pieter Bruegel the Elder.

The metaphor had proverbial status in antiquity and a similar metaphor occurs in the Katha Upanishad

Katha Upanishad

The Katha Upanishad , also titled "Death as Teacher", is one of the mukhya Upanishads commented upon by Shankara. It is associated with the school of the Black Yajurveda, and is grouped with the Sutra period of Vedic Sanskrit. It is a middle Upanishad...

: "Abiding in the midst of ignorance, thinking themselves wise and learned, fools go aimlessly hither and thither, like blind led by the blind."