a-men' (in ritual speech and in singing a-men', a'men) ('amen; amen, = "truly," "verily"): Is derived from the reflexive form of a verb meaning "to be firm," or "to prop." It occurs twice as a noun in Isa 65:16, where we have (the King James Version, the Revised Version (British and American)) "God of truth." This rendering implies the pointing 'omen or 'emun i.e. "truth," or "faithfulness," a reading actually suggested by Cheyne and adopted by others. "Amen" is generally used as an adverb of assent or confirmation--fiat, "so let it be." In Jer 28:6 the prophet endorses with it the words of Hananiah. Amen is employed when an individual or the whole nation confirms a covenant or oath recited in their presence (Nu 5:22; De 27:15 ff; Ne 5:13, etc.). It also occurs at the close of a psalm or book of psalms, or of a prayer.
⇒See a list of verses on AMEN in the Bible.
That "Amen" was appended to the doxology in the early church is evident both from Paul and Rev, and here again it took the form of a response by the hearers. The ritual of the installation of the Lamb (Re 5:6-14) concludes with the Amen of the four beasts, and the four and twenty elders. It is also spoken after "Yea: I come quickly" (Re 22:20). And that Revelation reflects the practice of the church on earth, and not merely of an ideal, ascended community in heaven, may be concluded from 1Co 14:16, whence we gather that the lay brethren were expected to say "Amen" to the address. (See Weizsacker's The Apostolic Age of the Christian Church, English translation,II , 289.)
James Millar