Between March 7th and October 17th in 1954, Hugh Nibley delivered a series of 30 weekly lectures on KSL Radio that were also published as pamphlets. The series called “Time Vindicates the Prophets” was given in answer to those who were challenging the right of members of the Church of Jesus Christ of Latter-day Saints to call themselves Christians.
This lectures talks about Hebrews 6:4, 6. It suggests that it is possible for men to be gifted with everything only to later lose everything; then, it is not possible for them to regain those blessings by their own works.
All 32 recordings are available immediately in the Complete Bibliography for Hugh Nibley (CBHN) at https://interpreterfoundation.org/bibliographies/hugh-w-nibley/lectures/