The reference would be D&C 138:10. The phrase in D&C 76: 73 needs to be read with verses 74-75.
73 And also they who are the spirits of men kept in prison, whom the Son visited, and preached the gospel unto them, that they might be judged according to men in the flesh;
74 Who received not the testimony of Jesus in the flesh, but afterwards received it.
75 These are they who are honorable men of the earth, who were blinded by the craftiness of men.
Everyone captive in spirit prison may be freed and enter the highest kingdoms. Those in the terrestrial receive the testimony of Jesus eventually, but may still hold to some preferences (whether to live without law or with the blindness implanted by craftiness) into the next life. That is up them; freedom, law and vision will not be forced upon them.