What are the Acrostic Psalms?

An acrostic is a poem in which the initial letters of each successive line form a word, phrase, or pattern. The acrostic Psalms tend to use the twenty-two letters with a few slight variations, of the Hebrew alphabet - the first word of the first verse beginning with aleph, the first word of the second verse beginning with bet, and so on.

There are numerous clear instances in the Old Testament: Psalms 25; 34; 37; 111; 112; 119; 145; Proverbs 31:10-31; Lamentations 1-4. (Some count Psalms 9 and 10).

Psalm 119 is the most complete acrostic psalm. It is the longest chapter of the Bible. It is divided into 22 sections, each titled after a letter of the 22 letters of the Hebrew alphabet. Each of these sections has eight verses:

1. Aleph (Psalm 119:1-8)
2. Beth (Psalm 119:9-16)
3. Gimel (Psalm 119:17-24)
4. Daleth (Psalm 119:25-32)
5. He (Psalm 119:33-40)
6. Waw (Psalm 119:41-48)
7. Zayin (Psalm 119:49-56)
8. Heth (Psalm 119:57-64)
9. Teth (Psalm 119:65-72)
10. Yodh (Psalm 119:73-80)
11. Kaph (Psalm 119:81-88)
12. Lamedh (Psalm 119:89-96)
13. Mem (Psalm 119:97-104)
14. Nun (Psalm 119:105-112)
15. Samekh (Psalm 119:113-120)
16. Ayin (Psalm 119:121-128)
17. Pe (Psalm 119:129-136)
18. Tsadhe (Psalm 119:137-144)
19. Qoph (Psalm 119:145-152)
20. Resh (Psalm 119:153-160)
21. Sin / Shin (Psalm 119:161-168)
22. Taw (Psalm 119:169-176)

Why an acrostic? Boice states:

We can think of several reasons. (1) It may be an artistic device used to add a certain beauty to the psalm, as rhyme does in our poetry. (2) It may indicate that the subject is being covered completely, from A to Z, as we might say. This is a particularly attractive possibility in regard to Psalm 119, which explores the nature and value of the written Word of God exhaustively. (3) The acrostic may have been a mnemonic device designed to assist the young in learning the psalms. That is probably why many Old Testament passages are poetry rather than prose. Poetry is easier than prose to memorize [note Psa 25 is for "learning" the A, B, Cs of discipline].