Hebr. Adv.
verily, of a truth, so be it, LXX 1 Ch. 16.36; at beginning of sentence, Ev. Matt. 5.18, al. ; doubled, Ev. Jo. 1.51, al. ; τὸ ἀ. 1 Ep. Cor. 14.16.

ἀμήν, indecl. (Heb. אָמֵן, verbal adj. fr. אמן, to prop. ni., be firm),
[in LXX: 1Ch.16:36, I Est.9:46, Neh.5:13 8:6, Tob.8:8 14:15, 3Ma.7:23, 4Ma.18:24 (elsewhere 'א is rendered ἀληθινός, Isa.65:16; ἀληθῶς, Je 35 (28):6; γένοιτο, Num.5:22, Deu.27:15ff., 3Ki.1:36, Psa.40 (41):13 71 (72):19 105 (106):48, Jer.11:5)*.]
__1. As adj. (cf. Is, l.with), ὁ ἀ., Rev.3:14.
__2. As adv.,
__(a) in solemn assent to the statements or prayers of another (Nu, Ne, etc., ll. with): ὁ ἀ., 1Co.14:16;
__(b) similarly, at the end of one's own prayer or ascription of praise: Rom.1:25 15:33, Gal.1:5, 1Ti.1:17;
__(with) in the Gospels, exclusively, introducing solemn statements of our Lord, truly, verily: Mat.5:18, 26 Mrk.3:28 (see Swete, in l.), Luk.4:24, al.; ἀ. ἀ., always in Jhn.1:52 3:3 5:19, al.; τὸ ναί, καὶ . . . τὸ ἀ., 2Co.1:20 (on usage in π., see MM, VGT, see word).
(AS)