Self-purification
When you have succeeded in acquiring this pure trait (that is exercising and nurturing the tongue), saved yourself from gossip and bad-mouthing, from profanity, futility, slander and such diseases and thorns of the tongue, you have, indeed, banished a heinous and condemned trait from yourself, then you can believe that you have made a significant achievement in the path towards truth and verity. Because self-purification, nurturing and exercise are some of our greatest battles (considering our destiny), and they very well might be more challenging and more terrifying than fighting with others. However, success in these battles is more valuable. So, a person who has attained such victory should consider himself blissful, and he should be confident that he has found the path towards felicity. Not only did he benefit himself, but he also did not disturb others.
A person of such traits realizes that he has banished his animalistic temperament through exercise and has achieved the attributes of humanity. Are you not happy with such exercise?