The Fundamental Differences
Grace: Infused vs. Assisted
In Catholic soteriology, grace is a real participation in the divine life — infused into the soul, transforming it from within. In LDS theology, grace is primarily Christ's "enabling power" that assists human effort, and it is insufficient without the completion of all required ordinances and lifelong faithfulness. The LDS formula is grace after all we can do (2 Nephi 25:23).
The Goal: Vision vs. Deification as Gods
The Catholic heaven is the Beatific Vision — the direct, loving knowledge of God as He is. The redeemed remain creatures; God remains Creator. In LDS theology, the ultimate goal is for humans to become gods of the same type as Heavenly Father — presiding over their own worlds with their own spirit children. These are fundamentally different ultimate destinies.
Temple Exclusion vs. Universal Sacramental Access
In Catholicism, all seven sacraments are available to every Catholic in every parish worldwide. In LDS theology, the most essential ordinances (Endowment, Celestial Marriage) require a temple recommend — denied to those who fall short of worthiness standards, miss tithing payments, or are not "active" members. Non-members (including family) cannot attend LDS temple weddings.
Finality of Death vs. Spirit Prison Second Chance
Catholic theology holds that death finalizes the soul's fundamental disposition toward God — purgatory purifies, but does not change the fundamental choice made in life. LDS theology offers a "second chance" in the Spirit Prison, where the departed can hear the gospel and accept proxy ordinances performed by living members. "It is appointed for men to die once, and after that comes judgment" (Heb. 9:27).