In plain words
The arrow he loosed struck the buck, and it died. The doe went weeping to her mother: “Mother! While the two of us were playing happily together, the King of Kekaya killed my husband. What will become of me now?” she said. Then that mother deer: “My child! In the world hardship and happiness, the two, are found together. We must not be crushed by hardship and loss. We must bear them, push through them and go forward,” she said, consoling her child. Then she herself went to the King of Kekaya: “King! Whoever it may be, there is no escape from experiencing the fruit of karma. What I have done I cannot escape; what you have done you cannot escape. So, just as I now grieve at my son-in-law's death, in time to come you too will have to grieve at your son-in-law's death,” she cursed him. That very deer was born as Mantharā and became the cause of the death of Daśaratha, the King of Kekaya's son-in-law.
Pravṛtti and nivṛtti
Human life is like an ocean full of towering waves of union and separation. So hardship and loss are unavoidable for anyone. This is the Dharma of pravṛtti. But the Dharma of nivṛtti is something else. When a child says, ‘Mother, I am hungry’, ‘My child! eat your food, and your hunger will go’, says Mother Pravṛtti. But Mother Nivṛtti does not speak that way. ‘My child! If you are hungry, eat your food. But enquire well what food to eat, and when, where and how, and eat food that is wholesome and moderate’, she counsels. If you eat everything that comes to hand because you feel hungry, your stomach is upset. We must eat food that does no harm to health. This is the Dharma of nivṛtti. The Veda too teaches well the principle of pravṛtti and nivṛtti.
There is nothing wrong in wanting what we need. But desire must have a limit. Along with the limit, we must keep to a measure. We must not say whatever comes to our lips.