If a knight drops his swords, he retrieves it without hesitation in order to protect himself.
If a snake falls in your lap, you instantly jump up in order to avoid getting bit.
If there is a chance you might lose the game, you push harder than ever, rally caps on.
If we cut ourselves, we use extra caution to clean and dress the wound, applying ointment day and night to prevent infection.
And yet, when we drop our mindfulness we are not in a hurry to retrieve it.
And yet, when negative emotions befall our mind we continue to indulge them.
And yet, when we actually lose our patience we let anger rule the show, and keep winning.
And yet, when we cut off generosity we don't care about the ensuing infection. Who cares?
Diligence is important. This is known amongst ordinary men and even the Buddha's praise it. The Exhortation to Wholehearted Resolve Sutra says:
Always rely upon noble joyous perseverance,
Which clears away all suffering and darkness,
Which is the basis of freedom from miserable realms,
And which is praised by all the buddhas.
One who joyously perseveres,
Has no difficulty accomplishing any project
Whether mundane or supramundane,
Who among the learned is disheartened by joyous perseverence?
If we do not persevere in overcoming our own shortcomings, how can we achieve our own aims, much less the aims of others?