In plain words
It is reflection in the mind that is most necessary. Only when we develop good thoughts can we set it on the good path. The great souls of those days put every kind of thought to use, each in its own noble way. They held anger to be very bad; but even that anger is not bad. Taken with an eye to time and occasion, that anger proves very helpful. They used to think forbearance and compassion very good. But we must use forbearance and compassion too with an eye to time and occasion. Otherwise even forbearance and compassion turn bad. Durvāsa looked upon his anger as tapas. That tapas he held to be fire. This anger he held to be water. Tapas is fire; anger is water. Now water can put out fire. At certain times we can produce fire in water itself. So fire in water and water in fire are merged in each other. It is in the way we use them that good and bad take shape. Even anger free of selfishness brings about a most noble path. Anger bound by Dharma does only good. To drive away others' Ajñāna, Ahaṅkāra, envy and such possessive feelings, we have to use this anger to some extent. The anger of great souls has done nothing but good. The reason is that they used it with an unselfish feeling. To develop our sacred works, to put down man's wicked conduct, to wipe out Ajñāna and Ahaṅkāra, to protect others: for these we have to use anger at certain times and occasions. All of Durvāsa's anger did only good. So he used this anger in this unselfish way. Even though we use anger, when we use it without leaving Satya, without breaking Dharma, in this unselfish way, it travels on the sacred path alone.
In the same way Śānti, forbearance and compassion. At certain times these work against certain Dharmas. If a king skilled in ruling takes up these three, this kindness, this compassion, this forbearance, his very rule comes to a standstill.