As a Biblical reference to this concept, we can look at the Prodigal Son...a kid who takes his riches and goes of to live a life of total debauchery, turning against everything his father taught him. But when he blows through his money, and recognizing that evil he has wrought within his own life, he comes crawling back home. Now, he doesn't come crawling back home asking for more...he basically tells his father he'll become his slave, he'll do whatever is asked of him, because he truly recognizes his undeserving nature...and in so doing he gives props to his father and acknowledges that his father was right, and gives love to his father.
His father's reply is to look past his vast multitude of sin an corrupt behavior, and love him completely and openly without condition in return.
That is how God wants it....he lets evil exist, *must* let evil exist, so that the prodigal son, everyone, can recognize how lost and wisked they are alone, and have one true moment of love for God, in which moment God restores the relationship with them eternally.
Really, it's not such a bad deal.