Sentence:  I join therefore in the public Assemblies, not because of the "Purity", or "Perfection" of that which is "done", or to "be found" there, but because of that which is "meant" and "intended" by them: They mean the holy, public Worship of God; they mean the Edification of Christians; they are of great Use to many People; they keep the World from a total Forgetfulness of God; they help the Ignorant and <WSD>Letterless</WSD> to such a Knowledge of God, and the Scriptures, as they would not have without them. 
Meaning of the word marked with <WSD> tags:  Illiterate.