To open the blind eyes,.... Of the idolatrous Gentiles, who were spiritually blind, and knew not the wretchedness of their case; the exceeding sinfulness of sin; their need of a Saviour, and who he was; as they did, when their eyes were opened by means of the Gospel sent among them, through the energy of the divine Spirit; for this is a work of almighty power and efficacious grace:to bring out the prisoners from the prison; who were concluded in sin, shut up in unbelief, and under the law, the captives of Satan, and held fast prisoners by him and their own lusts, under the dominion of which they were:and them that sit in darkness out of the prison house: of sin, Satan, and the law; being under which, they were in a state of darkness and ignorance as to things divine and spiritual.
The allusion is to prisons, which are commonly dark places.