Imprecatory Psalms

A number of psalms and some sections in the psalms have been labeled as 'imprecatory', which means they call for judgment, calamity or curses on ones enemies. The New Testament instructs us to bless our enemies and not to curse. Are we then to ignore or set aside these psalms? If not, then what place do these passages have in our lives? We will wrestle with these questions in Sunday School.