_____
The prophet Samuel wrote those words during the reign of King David more than 3,000 years ago. The fulfillment of it came true with the resurrection of our Lord Jesus!
Jesus, fully man, and fully God, came from the line of King David through the lineage of His mother, Mary. As God, He is eternal.
On the other end of the spectrum, we have Joseph Smith who claimed man is eternal, and had himself crowned as prophet, priest, and king. You’ll want to share the two examples with a Mormon and ask what they think of Smith’s failed prophecies.
_____
Gospel Through the Ages, p. 126; “Life, intelligence, mind, the “light of truth,” or whatever name one gives to the center of the personality of man, is an uncreated, eternally existent, indestructible entity. “He—for that entity is a person—. . . is eternal as God is; co-existent, in fact, with God; of the same kind of substance or essence with Deity, though confessedly inferior in degree of intelligence and power of God.”” – Milton Hunter
Joseph will be Prophet, Priest and King
The Essential Joseph Smith, p 201; “Last Monday Morning certain men came to me. “Bro[ther] Joseph[,] Hyrum is no prophet. He cant lead the church” You must lead the church. If you resign[, etc.] I felt curious and said here we learn in [the church about] a priesthood after the order of Melchisedeck—Prophet, Priest and King, and I will advance from Prophet to Priest and then to King not to the kingdoms of this Earth but of the most High God.” [sic]