Lamentations 1:21c-22 "Bring about the day of judgment that you promised so that they may end up like me! Let all their wickedness come before you; afflict them just as you have afflicted me because of all my acts of rebellion. For my groans are many, and my heart is sick with sorrow." (NET)

Lamentations 3:64-66 "Pay them back what they deserve, O Lord, according to what they have done. Give them a distraught heart; may your curse be on them! Pursue them in anger and eradicate them from under the Lord's heaven."

How do we reconcile these words with the words of Jesus in Matthew 5?

Matthew 5:43-44 "You have heard that it was said, 'Love your neighbor' and 'hate your enemy.' But I say to you, love your enemy and pray for those who persecute you"

What we understand from the nature of scripture is that it is inspired by God, so do we have a problem here?  Is there a contradiction?

What we see in Lamentations is Jeremiah emotionally pleading with the Lord to have mercy on the people.  He has moments when he realizes that Jerusalem has brought this on herself and also acknowledges that the Lord is just in his judgments (Lamentations 3:21-40).  He also has moments when he sins and curses his enemies as he blames them for the judgment caused by the sin of Israel.

At the writing of this book it appears that the Lord had gone silent (2:9) as his judgment of Jerusalem continued.  So we have the words of Jeremiah as he struggles with the wrath of God, and also trying to pray the wrath of God on those nations persecuting them.

The book of Lamentations being inspired does not exclude it from documenting truthfully the wrong thinking of Jeremiah.  The book of Lamentations is inspired scripture, Jeremiah was moved by the Spirit to write what God wanted written.  It is free from error and truthfully tells of Jeremiah's state experiencing God's judgment. 

But Jeremiah was still a sinner as were all the writers of scripture.  Remember Job and how he also accused the Lord of wrong doing?  We see a similar thing in Lamentations.  What is written is for our learning (2 Tim 3:16); Jeremiah had moments of failure when he suffered discipline from the Lord. 

May God give us the grace to respond to his discipline correctly and still love those who are used by God to discipline us.