As early as February 1825 the Presbytery was called on, in glowing terms, to
bless the Lord for the displays of sovereign grace which have been made <within our boundaries> during the past year. In the congregation of Palmyra, the Lord has appeared in his glory to build up Zion. More than a hundred have been hopefully brought into the kingdom of the Redeemer.
Thus, "building up Zion" is a revivalist term for growing the church. And the LDS with its millenial imprint is a literalization of that revivalist feeling.