
Before I proceed to the third and final 'installment' on this question, addressing (ever so briefly) the messianic character of the Psalter and the New Testament's usage of the imprecatory psalms in particular, I feel I should make one more comment about retribution and love.
There's a saying so axiomatic among Christian circles that you might mistake it for a Bible verse: "God hates the sin, but loves the sinner." Lewis argues along these lines in pp.32-33, stating that God has the same "implacable hostility which these poets express," yet, His hostility is "not to the sinner but to the sin." While the psalmists erroneously conflated their hatred of evil with the evildoer, Lewis argues, God does not.
Or doesn't He? According to Psalm 5:4-6,
"For you are not a God who delights in wickedness; evil may not dwell with you. The boastful will not stand before your eyes; you hate all evildoers. You destroy those who speak lies; the Lord abhors the bloodthirsty and deceitful man." Cf. Ps.11:5It is even said that God "hates" Israel, his own covenant people, in their obstinate disobedience (Jer.12:8; Hos.9:15).
For the sake of time and space, I don't want to get into the question of what exactly Scripture means by "hate" (cf. Mal.1:3; Lk.14:26; Mt.6:24), and what it could mean that God "hates" those whom he also, in some real sense, loves (Mt.5:43-48). It is unquestionably the case that God has a holy hostility, not merely towards sin per se - as though it existed in isolation from culpable, moral agents - but against the sinner. It is, after all, extremely difficult to extricate "the lying tongue," or "hands that shed innocent blood," or "haughty eyes," or "a heart that devises evil," etc., from the owners (Prov.6:16-18, 19). Nevertheless, it is also clear that God loves the objects of His wrath(e.g., Jn.3:16, 18, 36; Eph.2:3-4; 2Co.5:18-20; Rom.5:10)! It is enough now to simply observe that God both hates and loves sinners in ways that are not mutually exclusive.
As a result, one has a difficult time answering the question, "Is it wrong for the saints to share God's holy hostility toward the wicked?" - even if that participation is incomplete - in the affirmative. The psalmists clearly presented such 'shared hostility' not only as a commendation to God in their consciences regarding their own righteousness, (e.g., Ps.26:4-5), but as a participation in the righteous character of God Himself (e.g., Ps.139:29; 119:113). It was God-like.
And on this note, the messianic import of the Psalter is especially relevant. For the Psalms represent not merely the idealized piety of Israel's "everyman," but specifically that of the Davidic King. Not only is David the speaker in many cases, but the promised royal "Son of David" is often the focus. In fact, as Tremper Longman III writes, it is "significant that so much of the Psalter is connected with the institution of kingship in Israel and more specifically with David and his dynasty." The covenant with David (and, subsequently, the Temple complex and worship designed by him and implemented by his son, Solomon) provides the determinative theological and historical context of the whole Psalter (2Sam.7; cf. Ps.2; 45; 72; 89; 110; 132). In fact, the psalms could be summarized as instructions for life under God's reign - the kingdom of God - as experienced in and administered through the Davidic king.
In this covenant, God promises to establish David and "his son" as the anointed king (messiah) in Israel, the royal "son of God," through whom all the divine promises to the patriarchs would be fully and finally realized (e.g., cf. Ge.12:2-3; Ps.72:17; and Ge.15:13-21; 2Sam.7:10-11). David's earthly rule would not only represent God's heavenly kingdom in the world, but would anticipate (and partially realize) its fulfillment, "on earth as it is in heaven." Therefore, because of this close identification between the throne in Jerusalem and the throne above, David's enemies would become the enemies of God (see 2Sam.22:41; Ps.18:40; 89:23; cf. 2Sam.7:9), and vice versa. In other words, to become an enemy of the Davidic king was "nothing personal," merely, but rather an official stance against the whole elect nation of Israel, and more than that, against heaven itself (see Ps.2:1-12)!
This goes a long way in explaining the supposed naivety of the psalmists in so closely identifying their enemies with God's (pp.31-32, Reflections on the Psalms). Beyond simply the individual experience of the royal Davidide, due the corporate solidarity of the people with their King, and our solidarity with Christ by faith in particular, the enemies of the saints become the enemies of our King and of our God, and vice versa. It is very telling that when the sovereign, resurrected Christ confronts Saul on his path of persecuting the young church, His first words are, "Saul, Saul, why are you persecuting me?" Our naivety, perhaps, is more to be found in our loose and cavalier identification of who are enemies are.
When we turn to the New Testament, we find this messianic reading of the Psalter confirmed in the teachings of Jesus himself (Lk.24:44, 25-27; Mt.22:41-46), and in the apostles' subsequent preaching (e.g., Ac.2:25-31; 13:22-39). Note especially in these interpretations the prophetic role David, as author, plays with respect to his coming, "Greater Son." In fact, of the passages Lewis cites in his essay (Ps.109, 69:23; 143:12; 137:8-9; 139:19; and 23:5), two of them are explicitly used in the New Testament in reference to Christ, the messianic king. It is enlightening to observe how they are applied.
One of the remarkable things about the davidic psalms is the reality of suffering and persecution. The great and powerful king of Israel can write, "I am poor and needy," "my enemies surround me," "those who hate me without cause outnumber the hairs of my head," "my throat is parched from calling out to you," "deep waters have engulfed me," and most famously, "my God, my God, why have you forsaken me?" The messianic king is also the suffering servant of the Lord. It is typically in these "lamentations" that David cries out for vengenance against his enemies (though, note also Ps.2:7-12 and 110:1-6; cf., Ac.2:34-35; Eph.1:22; 1Cor.15:25-27; Heb.1:5-13; 10:13; Rev.12:5; 19:15). And the early church understood these prophetic descriptions of the individual and corporate enemies of David and his kingdom as anticipating and even precisely predicting the world's rejection and persecution of the Christ (e.g., see Acts 4:25-30).
Psalm 109:8 is cited by Peter in reference to Judas' betrayal in Acts 1:20. Jesus also cites Psalm 69:4 (cf. 109:3) in reference to his enemies in John 15:25. Similarly, Paul cites specifically Ps.69:22-23 in Romans 11:7-9, in describing those within Israel that have been 'hardened' in their response to Christ, having stumbled over God's chosen "cornerstone" (Rom.9:32-33; cf. 1Pe.2:6-8; Isa.28:16; Ps.118:22). Lastly, though Ps.137 is not directly referenced in the NT, we do read of the eschatological judgment of "Babylon" - the archetypal picture of 'civilized' evil - in which the Great City is finally repaid in full for all that it has done (Rev.18:6-7; cf. Ps.137:8-9). And what is the response of heaven to this terrifying judgment? "Rejoice over her, O heaven, and you saints and apostles and prophets, because God has pronounced judgment for you against her," Rev.18:20.
By looking at how the NT employs these verses, we see that these were understood by the early church as not only appropriate "Christian" texts, but as deeply Christological texts - functioning as messianic prophecy in disclosing both the coming reality of Christ's humiliation, in His rejection and sufferings, and, in his glorification, the destiny of all who oppose Him (e.g., Lk.19:27). Christ will rule in the midst of enemies (Rev.11:15-18; 19-22). And we, like the psalmists, cry out to God against the enemies of His people and of His Christ, praying for the grace and power to overcome, in order that we might rule with Him (Rev.2:27; 5:10; 20:6; 22:3-5; cf. 1Co.6:3).

