The first three pāramī or perfections (generosity, morality, and patience) are concerned with our actions of body, speech, and mind; the next three (energy, concentration, and wisdom) are focused inward. By developing the latter three of these pāramī, we strengthen all the interpersonal qualities we want to embody. It’s a reciprocal relationship; the more attentive we are to the wholesomeness (or not) of our words and actions, the more inclined we are to the cultivation of inner peace and wisdom. And the more we nurture our inner resources, the more naturally we will behave in harmonious ways.
The pāramī of viriya, (vigor, energy, strength) is what’s required of us to develop the path in ourselves. However, we’re not talking about bodily strength, but mental strength, which we may be unaccustomed to attending to.
From https://www.accesstoinsight.org/lib/authors/bodhi/waytoend.html#ch5
Energy (viriya), the mental factor behind right effort, can appear in either wholesome or unwholesome forms. The same factor fuels desire, aggression, violence, and ambition on the one hand, and generosity, self-discipline, kindness, concentration, and understanding on the other. The exertion involved in right effort is a wholesome form of energy, …
Time and again the Buddha has stressed the need for effort, for diligence, exertion, and unflagging perseverance. The reason why effort is so crucial is that each person has to work out his or her own deliverance. The Buddha does what he can by pointing out the path to liberation; the rest involves putting the path into practice, a task that demands energy. This energy is to be applied to the cultivation of the mind, which forms the focus of the entire path. …
The nature of the mental process effects a division of right effort into four “great endeavors”:
- to prevent the arising of unarisen unwholesome [mind] states;
- to abandon unwholesome [mind] states that have already arisen;
- to arouse wholesome [mind] states that have not yet arisen;
- to maintain and perfect wholesome [mind] states already arisen.
The four great endeavors remind me of a story:
An old Cherokee is teaching his grandson about life. “A fight is going on inside me,” he said to the boy. “It is a terrible fight and it is between two wolves. One is evil – he is anger, envy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority, lies, false pride, superiority, and ego.”
He continued, “The other is good – he is joy, peace, love, hope, serenity, humility, kindness, benevolence, empathy, generosity, truth, compassion, and faith. The same fight is going on inside you – and inside every other person, too.”
The grandson thought about it for a minute and then asked his grandfather, “Which wolf will win?”
The old Cherokee simply replied, “The one you feed.” (https://www.urbanbalance.com/the-story-of-two-wolves/)
By feeding our “good wolf”, we are starving our “evil wolf”. We move along the path towards awakening by being vigilant about our intentions, the stories we tell ourselves, and the diligence with which we train our minds. This is the type of energy and effort the Buddha recommends.
The Buddha's Advice to Laypeople 