The restoration of the Jews, or more correctly the house of Israel, and the fulfilment of the covenant God made with their fathers, is a central tenet of Mormonism. It is in fact the key to the understanding of the Book of Mormon. The primary object of the Book of Mormon is internally presented as being the means (or one of the means) of facilitating that restoration, and the fulfilling of that eternal covenant God made with Abraham, Isaac, and Jacob concerning their descendents in the latter days. The Jews, or the house of Israel, are to be restored to the lands of their inheritance, and ultimately to the true gospel. That is the primary message of the Book of Mormon, which it is designed to facilitate.
One of the interesting episodes of Mormon history is the commission Joseph Smith gave to LDS Apostle Elder Orson Hyde to travel to Jerusalem, and dedicate the land for the return of the Jews. Here is an interesting
link on the subject.
The full text of dedicatory prayer can be read
here.
Spencer W. Kimball Dedicates Hyde Memorial Garden in Jerusalem
here.