I. THE TERM ECCLESIA
In order to understand the precise force of this word, something must first be said as to its employment by the Septuagint translators of the Old Testament. Although in one or two places (Psalm 25:5; Judith 6:21; etc.) the word is used without religious signification, merely in the sense of “an assembly”, this is not usually the case. Ordinarily it is employed as the Greek equivalent of the Hebrew qahal, i.e., the entire community of the children of Israel viewed in their religious aspect. Two Hebrew words are employed in the Old Testament to signify the congregation of Israel, viz. qahal 'êdah. In the Septuagint these are rendered, respectively, ekklesia and synagoge. Thus in Proverbs v, 14, where the words occur together, “in the midst of the church and the congregation”, the Greek rendering is en meso ekklesias kai synagoges. The distinction is indeed not rigidly observed – thus in Exodus, Leviticus and Numbers, both words are regularly represented by synagoge – but it is adhered to in the great majority of cases, and may be regarded as an established rule. In the writings of the New Testament the words are sharply distinguished. With them ecclesia denotes the Church of Christ; synagoga, the Jews still adhering to the worship of the Old Covenant. Occasionally, it is true, ecclesia is employed in its general significance of “assembly” (Acts 19:32; 1 Corinthians 14:19); and synagoga occurs once in reference to a gathering of Christians, though apparently of a non-religious character (James 2:2) But ecclesia is never used by the Apostles to denote the Jewish Church. The word as a technical expression had been transferred to the community of Christian believers.
Hope this helpsIt has been frequently disputed whether there is any difference in the signification of the two words. St. Augustine (in Psalm. lxxvii, in P. L., XXXVI, 984) distinguishes them on the ground that ecclesia is indicative of the calling together of men, synagoga of the forcible herding together of irrational creatures: “congregatio magis pecorum convocatio magis hominum intelligi solet”. But it may be doubted whether there is any foundation for this view. It would appear, however, that the term qahal, was used with the special meaning of “those called by God to eternal life”, while 'êdah, denoted merely “the actually existing Jewish community” (Schürer, Hist. Jewish People, II, 59). Though the evidence for this distinction is drawn from the Mishna, and thus belongs to a somewhat later date, yet the difference in meaning probably existed at the time of Christ’s ministry. But however this may have been, His intention in employing the term, hitherto used of the Hebrew people viewed as a church, to denote the society He Himself was establishing cannot be mistaken. It implied the claim that this society now constituted the true people of God, that the Old Covenant was passing away, and that He, the promised Messias, was inaugurating a New Covenant with a New Israel.