In the Hebrew Scriptures the word is used as a solemn expression to obligate oneself legally to an oath or covenant and its consequences (Nu 5:22; De 27:15-26; Ne 5:13), also as a solemn expression to subscribe to an expressed prayer (1Ch 16:36), to an expression of praise (Ne 8:6), or to an expressed purpose (1Ki 1:36; Jer 11:5). Each of the first four books, or collections, of the Psalms concludes with this expression, perhaps indicating that it was customary for the congregation of Israel to join in at the end of the song or psalm with an “Amen.”​—Ps 41:13; 72:19; 89:52; 106:48.

The prayer expressed at 1 Chronicles 16:36 and those contained in the Psalms (41:13; 72:19; 89:52; 106:48), as well as the expressions contained in the canonical letters, all indicate the correctness of the use of “Amen” at the close of prayers. It is true that not all the prayers recorded show such conclusion, such as David’s closing prayer for Solomon (1Ch 29:19) or Solomon’s dedication prayer at the inauguration of the temple (1Ki 8:53-61), although such expression may well have been made. (Note 1Ch 29:20.) Similarly, its use is not recorded in Jesus’ prayers (Mt 26:39, 42; Joh 17:1-26) or in the prayer of the disciples at Acts 4:24-30. However, the weight of the prior evidence presented strongly indicates the rightness of the use of “Amen” as a conclusion to prayer, and Paul’s statement at 1 Corinthians 14:16 in particular shows that it was customary for those in Christian assembly to join in the Amen to a prayer. Additionally, the examples of those in heaven, recorded at Revelation 5:13, 14; 7:10-12; and 19:1-4, all give support to its use in subscribing to prayers or solemn statements and thereby, through the use of this one word, expressing the confidence, strong approval, and earnest hope that is in their hearts.