Psalms 59:11

Slay them not, lest my people forget -The meaning of this seems to be, Do not destroy them at once, lest, being removed out of the way, the people should forget what was done, or should lose the impression which it is desirable should be produced by their punishment. Let them live, and let them wander about, as exiles under the divine displeasure, that they may be permanent and enduring proofs of the justice of God; of the evil of sin; of the danger of violating the divine law. So Cain wandered on the earthGenesis 4:12-14, a living proof of that justice which avenges murder; and so the Jews still wander, a lasting illustration of the justice which followed their rejection of the Messiah.