What's happening
This revelation gives the Church its name — The Church of Jesus Christ of Latter-day Saints — by direct revelation, settling once for all what the restored Church should be called. It also calls for the gathering at Far West and the building of a temple there, and contains the luminous summons that the Church should arise and shine forth, that thy light may be a standard for the nations.
It was given at Far West on April 26, 1838. The Church had been known by several names since its organization in 1830 — the Church of Christ, the Church of the Latter Day Saints, the Church of God. Section 115 ends the ambiguity by revelation: for thus shall my church be called in the last days, even The Church of Jesus Christ of Latter-day Saints (v. 4). The name fuses the two essentials — it is the Church of Jesus Christ (His, bearing His name, the same Church He established anciently) and of Latter-day Saints (its members the saints, the covenant people, living in the latter days). The Lord then calls the saints to gather at Far West, to build a house unto me there (v. 8), and addresses them with the radiant call drawn from Isaiah 60: Arise and shine forth, that thy light may be a standard for the nations (v. 5).
The name revealed (verses 3–4)
For thus shall my church be called in the last days, even The Church of Jesus Christ of Latter-day Saints. — D&C 115:4
The name is given by the Lord Himself, and every part of it carries weight. It is The Church of Jesus Christ — His Church, called by His name, the same gospel and authority He established in the meridian of time, now restored. The Book of Mormon had taught the principle directly: how be it my church save it be called in my name? ... if it be called in my name then it is my church, if it so be that they are built upon my gospel (3 Nephi 27:8). A church must bear the name of Christ. And it is the Church of Latter-day Saints — for its members are saints (the New Testament word for the covenant faithful, hagioi), distinguished from the former-day saints only by the dispensation in which they live. The name is not a brand; it is a confession. It says whose the Church is (Christ's) and who its people are (His saints, in the last days).
Arise and shine forth (verses 5–8)
Verily I say unto you all: Arise and shine forth, that thy light may be a standard for the nations; And that the gathering together upon the land of Zion, and upon her stakes, may be for a defense, and for a refuge from the storm, and from wrath when it shall be poured out without mixture upon the whole earth. — D&C 115:5–6
Having named His Church, the Lord commissions it. Arise and shine forth echoes Isaiah 60:1 (Arise, shine; for thy light is come) — the call to a covenant people to become visible, radiant, a standard (a raised banner, an ensign) that the nations can see and gather to. And the purpose of the gathering is protection: the stakes of Zion are for a defense, and for a refuge from the storm. The image is tender — a people drawn together not to hide their light but to raise it, and in the gathering to find shelter. The Lord then calls for Far West to be built up and a house (temple) raised there (vv. 7–11), though the expulsion from Missouri would prevent it.
How the section is built
Eighteen verses. It opens addressing the leaders and the whole Church (vv. 1–4), and at its center gives the name — The Church of Jesus Christ of Latter-day Saints. It issues the commission and gathering (vv. 5–6): arise and shine forth, be a standard for the nations, gather for defense and refuge. And it gives specific direction for Far West (vv. 7–18): build up the city, raise a house unto the Lord, beginning the foundation on the appointed day. The architecture moves from identity to mission to place: first who the Church is (Christ's, the saints'), then what it is for (a light to the nations, a refuge), then where the next work lies (Far West). The naming at the center anchors everything — a Church that bears Christ's name, sent to shine.
How this sits in the documentary record
Where this lands
Section 115 is where the restored Church received its name — and the name is itself a sermon. The Church of Jesus Christ of Latter-day Saints. Strip it down and it says two things, both essential. It is the Church of Jesus Christ: it belongs to Him, bears His name, teaches His gospel, claims His authority; it is not the church of a man or a movement but of the Lord (how be it my church save it be called in my name?). And it is the Church of Latter-day Saints: its members are saints, the covenant people, the same in kind as the hagioi Paul wrote to, distinguished only by living in the last days. The name confesses both whose the Church is and who its people are. To wear that name is to claim Christ and to be claimed by Him.
And the commission that follows the naming is as bright as the name is weighty: Arise and shine forth, that thy light may be a standard for the nations. A Church named for Christ is not meant to be hidden; it is meant to shine, to be a raised banner the scattered can see and gather to, a refuge from the storm. That is the whole arc of Section 115 in one motion — a people given the name of Jesus Christ, and in the same breath sent to lift their light so the nations can find their way home. The name and the mission are inseparable: to be the Church of Jesus Christ is to arise and shine forth in His name, a standard set up so that all who are weary of the storm can come in.