In plain words
If we hope for something, something tied to disappointment is there as a cause of this hope. Human life is made of hope and disappointment. Or human life is made of resolves and their wavering. Human life is made of union and separation. So they have said that saṃsāra is an ocean of mighty waves, of the struggle of union and separation. In just such an ocean we find precious gems and pearls. Only when we bear it, push through it and go forward can we attain this divine state. If instead we tremble and shrink at everything, and cannot bring it about along the right path by any kind of sādhana, our life itself goes to waste. Many obstacles keep blocking our life. Without obstacles of this kind, human nature itself would have no value. So what gives human nature its value is sorrow, unrest and bad. "Kaṣṭe phale," they said. Without hardship we can gain no result of any kind. 'By sādhana all works are accomplished on earth,' they said in a short sentence. Sādhana means this alone: what we have to do. To turn bad into good. To turn sorrow into Ānanda. To shape bad into good. For this the mind is most necessary.
Man cannot recognise the mighty powers of the mind. The mind alone is the root cause of all happiness and sorrow. No one can describe the divine power in the mind as this or that. Beyond all description is the nature of the mind. In a moment it spreads everywhere. In a moment it stands still. In a moment it blossoms. In a moment it closes up. That is why: 'karmānubandhini manuṣyaloke'; in human nature the mind keeps being bound. By the mind itself the world is bound. 'Mano mūlam idaṃ jagat': the mind is the root cause of good and bad. Suppose we are taking food. We think this food gets digested and gives the body strength and contentment. No. Food is not what gives us strength and contentment. The mind itself. If, at the time we take this food, the mind is not cheerful, glad and joyful, all that food turns to poison. So what brings sacred divinity to human nature is the mind itself.