The Gospel was Restored

“God restored the fulness of the gospel to the earth in the nineteenth century through the Prophet Joseph Smith” (The Guide to the Scriptures, "Gospel," 96–97).” http://www.josephsmith.net

The Gospel is Complete

Jesus  said, “The law and the prophets were until John (no more prophets,): since that time the kingdom of God is preached, (in it’s fullness, no new revelations, no new ordinances, everything necessary for salvation has been revealed.) and every man presseth into it.”  Luke 16:16 (Revelation now comes to us by the Holy Spirit, not by prophets. See John 14:26)

"... I will build my church; and the gates of hell shall not prevail against it." Jesus, Matthew 16:18