Psalms 9:6

O thou enemy, destructions are come to a perpetual end: and thou hast destroyed cities; their memorial is perished with them.

The enemy is Satan and the wicked who follow him, and his rebellion with the ruin and destruction caused by sin is brought to a complete and perpetual end. Satan himself and all the wicked are cut off and destroyed, so that sin, its ruin, and those who clung to it all come to an end together. Their memorial perishes with them in that their names are forgotten and erased as they sink into eternal oblivion. This is a final end of sin and its consequences, not an eternity of continuing suffering. With no lost souls left to blaspheme God or to continue in rebellion, the praise of heaven and earth goes on undisturbed and the peace of the eternal state is never broken.