Ether 4

After Moroni has translated the writings of the Brother of Jared he is commanded to seal those plates so they cannot be opened. Moroni says "there were never greater things" shown unto man and that mankind will not have the interpretation of those sealed plates until world has repented of its sins and believes in the Lord. If the world will sanctify itself, then those words will be revealed. Verses 6 to 19 are a quotation from the Lord and he promises that great and marvelous things are reserved for us if we will believe in him.

When you study the scriptures, you come to know that certain covenants were made with the House of Israel that are to be fulfilled in the latter days. Certain things are to happen prior to the Lord's coming. Because of the apostasy of the church, the oppression of governments and of the Catholic Church against religious thought and practice, and the proliferation of protestant churches, there had to come a time when the Lord's true church had to be restored. For a restoration to happen, several things would have to take place. There would have to be prophets and revelation or the confusion concerning the Lord would continue. There had to be a return of the Lord's authority or priesthood so that the people were invested with that ability to do the Lord's work in his name and under his direction. Just as it was with the advent of new prophets in the past, new scripture would accompany the revelations received and this new scripture would be a sign and a testimony of the truthfulness of this being the Lord's work. All of these things have happened with each dispensation of the gospel in the past and they have happened in our day as well. And the Lord tells us in Ether 4, the Book of Mormon is a sign that the Lord's work has commenced in our day. The most important thing that we learn in the restoration is the true nature of God.