A few thoughts on the use of the imprecatory Psalms-- there always seems to be hesitancy on their appropriateness for the church, whether in private or corporate worship.
I think any hesitancy is only because people aren't understanding that Christ and his Church are the central figures of the Psalms; everything in them must be embraced through that lens in order to understand and make full use of them.
The imprecatory Psalms solemnly proclaim God's just and righteous judgments upon the wicked. They sometimes pronounce those judgments, as in Psalm 109, where the judgment upon Judas the son of perdition is foretold (see Acts 2:15-20). God will judge in the same way all who have despised and persecuted Christ and his Church. The Church, united to her Lord, speaks with his mind in praying for and pronouncing these judgments. And like him, the Church takes no pleasure in the death of the wicked (Ezekiel 33:11).
The imprecatory Psalms sometimes describe the sad outcomes of those judgments, when man is left to his own cruelty and the innocent suffer as casualties of war, as in Psalm 137:8, 9. These verses are not the voice of the church praying that babies will suffer and die. They were prophecy in the sense that they warned of and foretold the terrible future ahead for the little ones of cruel Babylon, when the equally cruel Medes and Persians overran and conquered them. They are still prophecy, an overarching truth of the consequences of man's pride and hatred toward God. The church is to continue to recount these things for her own sobriety and for the good of a lost world.
There is no sinful desire for revenge expressed in the Psalms. The psalmists' expressions are all prophetic, all of Christ, and all speak to the coming of his glorious kingdom. We can and should make use of them because we are to pray for and speak of the righteous judgments of God.
