The last sentence of the preceding verse should be read with verse 31:
…Wherefore, if they should have charity they would not suffer the laborer in Zion to perish. But the laborer in Zion shall labor for Zion; for if they labor for money they shall perish.
The common thread here is the laborer in Zion. To understand this requires an understanding of what Nephi means by the laborer in Zion. We may discern this from the specifics of the context, and from the specifics we find another point which looks both to the future and perhaps to Nephi’s past.
Nephi states that the laborer in Zion should labor for Zion. Zion is certainly a designation of the work of the Lord. Therefore the laborer in Zion is one who is engaged in the work of the Lord. Nephi is specifically arguing against the priestcrafts mentioned in verse 29. These are those who would labor not for Zion, but for money. Rather than a specific condemnation of a paid clergy, Nephi is contrasting the motives of those who labor. Note in verse 29 the “priestcrafts are that men preach and set themselves up for a light unto the world, that the may get gain and praise of the world; but they seek not the welfare of Zion.”