There is a category of Psalms called the “Imprecatory Psalms” (e.g. Psalms 5, 10, 17, 35, 58, 59, 69, 70, 79, 83, 109, 129, 137, and 140) from the verb “to imprecate.” This means to invoke a curse. In the context of the Bible, this means to call upon God to curse someone. There is a whole theology of it, which gives shape to proper interpretation and application for us. 

Contrary to popular uneasiness with such language, it is not sinful to pray or align one’s thoughts with; but then that raises that question about proper interpretation. One hint is that, much like with election and reprobation and the gospel call, so it is here. We do not know the ultimate identity of God's enemies, so that when we find that we have enemies too, it is a humble, God-trusting process to sort that out, love our enemies, and still hate God’s enemies in the concrete (and ours in the more provisional sense). How do we make sense of all of that?

Let me offer six premises which must be factored into any mature approach to imprecation. 

Premise 1. The Imprecatory Psalms are God-breathed Scripture and therefore included in that which is profitable for every believer unto every good work (2 Tim. 3:16-17). 

Premise 2. We are never at a loss for enemies that would do us violence; and when such is unintelligible, it is likely because we have made a false peace with the world. Therefore, such prayers are in the Scriptures as a regular storehouse for the beleaguered saints.

Premise 3. God alone knows the identity of the elect and the reprobate (2 Tim. 2:19).

Premise 4. Consequently, God alone knows which of his enemies will be transformed into his own beloved children (from 2).

Premise 5. We are to love all that God loves and hate all that God hates, never calling good “evil” or evil “good” (Isa. 5:20). 

Premise 6. If we can distinguish, in evangelism, between that which is under God’s wrath in unbelief, and that which may be saved through belief (and aim our gospel speech accordingly), then we can also distinguish between that which would be under God’s judgment in response to imprecation and that which would be under God’s mercy given repentance (and aim our prayer accordingly). 

So may we pray that God’s wrath be given to those currently opposing him and us?

In short, yes. While we may pray for God's justice to be done, even his wrath to be poured out, we must be careful not to pray that in the spirit that Jonah did, nor in the way that James and John requested on Jesus that lightning be sent to consume those not in their ranks: that is, in self-righteousness, or in a way that prizes our immediate sense of vindication over God's greatest glory.

More often than not, the details of those Psalms are reflections of the lex talionis—so that the violence planned by them blows up on them in full measure—and thus there is a poetic justice in the punishment requested: “In arrogance the wicked hotly pursue the poor; let them be caught in the schemes that they have devised” (Ps. 10:2). Would we be perfectly willing to call such moments “karma,” and begrudge the Judge of all the earth his right to to use the harm already set up by the devil’s assassins?

Let us not forget that one is in a desperate situation who would pray such prayers: “Give attention to the sound of my cry, my King and my God, for to you do I pray” (Ps. 5:2). Humility ought to already have been worked in the heart. No doubt, that may be mixed with thoughts of vengeance. However, the whole impetus for turning to these words of Scripture is that one is earnestly seeking the help of the Lord where there seems to be no more earthly resources. Perhaps that is time also to recognize that we have waited too long to depend on God. He does not owe us deliverance, but such would be a deliverance nonetheless.

Does God sometimes vindicate us in this life or only in the end?

Vindication is really closely associated with vengeance because they both seek justice, but there is a good desire for it and a sinful. The sinful would seek it apart from God’s timing or his valuation. The only difference would be that where vengeance seeks the punishment of justice, vindication seeks that the truth comes to light. While no one verse in the Bible defines true vindication for us, some do speak of it as good news: "For the LORD will vindicate his people" (Deut. 32:36); "Keep your conduct among the Gentiles honorable, so that when they speak against you as evildoers, they may see your good deeds and glorify God on the day of visitation" (1 Pet. 2:12).

We are only promised the vindication in the end. However, that is not to say that he does not do so at times. There are other Psalms and Proverbs about the wicked being trapped in the snares that they set forth for harm. There were also examples such as Haman in his plot against the Jews in Esther, or Saul in his unjust pursuit of David. I could not say how often, but there are times when things are brought to light in this age for sure. Ultimately, we have this promise: “He will bring forth your righteousness as the light, and your justice as the noonday” (Ps. 37:6). 

Those who would mute the Imprecatory Psalms would restrain (if they could) both God’s justice on those oppressors and his mercy on the oppressed. And let us not pretend that it has much to do with a high-minded or tender-hearted impulse toward one’s fellow man. It is an embarrassment of the word, pure and simple. It is a failure of nerve over the world’s worst crimes right under our noses. The critic of imprecation is not so much over-sensitive, as that he has a callous heart for those who need divine pity the most.