The Perfection of Energy - The characteristic of strengthening and supporting

All people have viriya, but if the Dhamma had not been taught the characteristic and the different aspects of viriya could not be known. Viriya has been explained as controlling faculty, indriya, because it is predominant as a support for the conascent dhammas.
Whenever kusala citta arises and someone performs an action with patience and diligence, viriya cetasika gives support at such a moment. One can perform one’s task without becoming disheartened. As the “Expositor” explained, the controlling faculty of viriya has the characteristic of strengthening and giving support.
If one develops panna one is supported by viriya so that one perseveres in the development of panna and all kusala dhammas. The “Expositor”(120) uses the simile of an old house that is strengthened and supported by new pillars. Evenso, when someone is supported by viriya, kusala dhammas will not decline in him.
If someone at this moment is bored, lazy, drowsy or disheartened, he should know that he is like an old building that is dilapidated, because he is not able to be firm in kusala and to apply himself to it. Viriya cetasika has the characteristic of strengthening and supporting just as a pillar supports an old house so that it is stable. Thus we see the characteristic of support of viriya. The “Expositor” uses several similes so that we can understand the characteristic of viriya cetasika that arises at this moment.
We read in the “Expositor” (121):

“As a small army going to battle might be repulsed,

then they would tell the king.

The king would send a strong reinforcement.

The king’s army, being thus supported, would defeat the hostile army.

Thus energy does not allow associated states to recede, to retreat;

it uplifts, supports them.

Hence has it been said that energy has the characteristic of supporting.”