As most LDS are aware, when the Eucharist is blessed in sacrament meeting, the priest kneels down to perform the prayer indicated in Moroni 4. Indeed, verse two indicates kneeling down “with the church” is the proper process. As per Moroni’s instruction, Mormon congregations joined in kneeling with the administrator until 1890-1900 (see also D&C 20:76). However, this was not the way Jesus taught them to do it. According to 3 Nephi 20:2, the administrator and congregation are supposed to “stand up upon their feet” when dispensing and partaking of the bread and wine. Moroni never explains why the church changed the direct commandment of Christ, nor is there any other indication of disregarding the Savior’s command during the 400 years that had elapsed.
~Thanks to Dan Vogel, Joseph Smith: The Making of a Prophet, page 365~