Right Effort
If your practice is good, you may become proud of it. What you do is good, but something more is added to it. Pride is extra. Right effort is to get rid of something extra.
The most important point in our practice is to have right effort or perfect effort.
Our effort is our practice should be directed from achievement to non-achievement.
When you make some special effort to achieve something, some excessive quality, some extra element is involved in it. You should get rid of excessive things.
By purity we just mean things as they are.
We should not attach to the attainment.
But if sound did not already exist before you clapped, you could not make the sound.
But if your effort is in the right direction, then there is no fear of losing anything.