It was during the time which intervened between the closing of the Old Testament canon and the opening of that of the New that συναγωγὴ acquired that technical meaning of which we find it in full possession when the Gospel history begins; designating, as there it does, the places set apart for purposes of worship and the reading and expounding of the Word of God, the ‘synagogues,’ as we find them named; which, capable as they were of indefinite multiplication, were the necessary complement of the Temple, which according to the divine intention was and could be but one. But to return to ἐκκλησία. This did not, like some other words, pass immediately and at a single step from the heathen world to the Christian Church: but here, as so often, the Septuagint supplies the link of connection, the point of transition, the word being there prepared for its highest meaning of all.
When the Alexandrian translators undertook the rendering of the Hebrew Scriptures, they found in them two constantly recurring words, namely, hdAfe and lhAqA. For these they employed generally, and as their most adequate Greek equivalents, συναγωγὴ and ἐκκλησία. The rule which they seem to have prescribed to themselves is as follows — to render hdf for the most part by συναγωγὴ (Exod. xii. 3; Lev. iv. 13; Num. i. 2, and altogether more than a hundred times), and, whatever other renderings of the word they may adopt, in no single case to render it by ἐκκλησία. It were to be wished that they had shown the same consistency in respect of lhq; but they have not; for while ἐκκλησία is their more frequent rendering (Deut. xviii. 16; Judg. xx. 2; I Kin. viii. 14, and in all some seventy times), they too often render this also by συναγωγὴ (Lev. iv. 13; Num. x. 3; Deut. v. 22, and in all some five and twenty times), thus breaking down for the Greek reader the distinction which undoubtedly exists between the words.
Our English Version has the same lack of a consistent rendering. Its two words are ‘congregation’ and ‘assembly;’ but instead of constantly assigning one to one, and one to the other, it renders hdf now by ‘congregation’ (Lev. x. 17; Num. i. 16; Josh. ix. 27), and now by ‘assembly’ (Lev. iv. 13); and on the other hand, lhq sometimes by ‘assembly’ (Judg. xxi. 8; 2 Chron. xxx. 23), but much oftener by ‘congregation’ (Judg. xxi 5; Josh. viii. 35).