In plain words
To turn sorrow into happiness is itself true sādhana. Without sorrow there is no happiness. Without bad, good does not come. Bad and good, happiness and sorrow: between the two a battle goes on without end. So no one can separate these two.
Hardship and happiness, the two are joined together; no one has the power to part them. Happiness on its own we shall never see anywhere; when hardship bears fruit, they call it happiness.
Hardship and happiness, the two live bound to each other, each the support of the other. One is the beginning. The second is the end. One is the start. The second is the end. The beginning cannot be without the end, nor the end without the beginning. Apart from divinity alone, the One without beginning or end, every worldly thing of Prakṛti has an end: objects, matters, occupations and joy. Sorrow is not something someone brings and drops on our heads. Nor do troubles. Bad is not something that comes from somewhere and settles in our heads. Bad and sorrow, these two arise of themselves. However sacred a thing may be, without sādhana it sinks down into a low state. However precious it may be, its value wastes away little by little. By sādhana alone does its value grow. A small diamond. Suppose we come upon it. But its value is very small. Only when we put it through many kinds of refining, only when we give it cuttings, does its value grow. Even gold is at first mixed with earth, in rock. When we put it through the sādhana called refining, it turns into pure fine gold and gets its true value. So by sādhana what is small attains greatness. What is in a low state reaches a high level. No one, the moment he is born, is learned, a scholar or a man of good qualities. Only by performing certain kinds of sādhana, little by little, is he able to become a man of good qualities and a learned man.
In the world, natural creation is made with bad alone. From this very bad, good arises. Without bad there is no chance for good to arise.