Moses 7:55-57; D&C 138:50; Teachings of the Prophet Joseph Smith, pp. 310-311; Journal of Discourses 1:289-290
“I know it is a startling idea to say that the Prophet and the persecutor of the Prophet, all go to prison together. What is the condition of the righteous? … They have a privilege of seeing and understanding more than you or I have, in the flesh; but they have not got their bodies yet, consequently they are in prison.” (Brigham Young, Journal of Discourses 3:95)
“The designation spirit prison may be said to have two meanings—hell, which is the prison proper; and the whole spirit world, in the sense that all who are therein are restricted and cannot gain a fulness of joy until after their resurrection (D&C 93:33-34).” (Bruce R. McConkie, Doctrinal New Testament Commentary, 3:309)