The last two verses (vv. 30, 31) are a powerful and effective ending to this admittedly difficult psalm. They anticipate the deliverance David has been asking for and promise that David will use his mouth to praise God for his deliverance. His accusers use their mouths to accuse and curse him. He will use his to extol and bless God.

When we pass from the opening stanza to the second, central portion of the psalm (vv. 6-20) we find an interesting change—quite apart from the curses. The references to David's enemies change from being plural (“they”) to being singular (“he,” “him” and “his”). This continues until verse 20 where the references become plural once again (“accusers”). What are we to make of this? It may be a Hebrew idiom meaning “each and every one of them,” which verse 20 seems to support since its return to the plural seems to be a summary. But it is more likely that David is speaking of a specific individual. The Apostle Peter took it this way when he viewed verse 8 as a prophetic reference to Judas Iscariot (in Acts 1:20).

Psalm 109 is the last of the imprecatory psalms. Imprecation has to do with praying for or calling down curses on one's enemies, which followers of Christ are not supposed to do. So for that reason the imprecatory psalms are among the most troubling parts of Scripture for Christians and Christian sensibilities.

The final stanza is a prayer for victory over Edom, which is what has probably been on the psalmist's mind from the first verse onward and is the occasion for this new composition. David had defeated Edom and made it a part of his kingdom years before this. The account of David's conquest is in 2 Samuel 8:1-14 (a parallel account is in 1 Chronicles 18:1-13). The relevant part of this chapter says, “David became famous after he returned from striking down eighteen thousand Edomites in the Valley of Salt. He put garrisons throughout Edom, and all the Edomites became subject to David. The LORD gave David victory everywhere he went” (2 Sam. 8:13, 14). But now the Edomites had apparently regained power, and a new battle was pending. The psalmist asks, “Who will bring me to the fortified city? Who will lead me to Edom?”

The first thing the author has to say is that his “heart is steadfast” or fixed. How so? It is not many verses further along before we learn the secret of his stability. It is because God is a steadfast or faithful God, and the psalmist's confidence is in him. Indeed, God is more than just steadfast. He is also a God of great love, and his love and faithfulness both reach as high as the sky or heavens, which is a way of saying that they are infinite and thus beyond our full comprehension: “I will praise you, O LORD, among the nations; I will sing of you among the peoples. For great is your love, reaching to the heavens; your faithfulness reaches to the skies.”