If any think they are religious, and do not bridle their tongues but deceive their hearts, their religion is worthless.  Religion that is pure and undefiled before God, the Father, is this: to care for orphans and widows in their distress, and to keep oneself unstained by the world.

The Word urges us on toward truth.  And truth is having a mind, heart and mouth which are united.  Being stained by the world means believing that Jesus is Lord in our hearts but being uncharitable toward our neighbor with our mouth or deeds.  Being stained by the world means adopting a worldly way of thinking: that this or that act means nothing, that nobody will ever notice.  It means letting our love grow cold because of all the evil we see around us.  We are even told this explicitly by Christ: "And because of the increase of lawlessness, the love of many will grow cold."  (Matthew 24.12)

We are commanded to be lights in the world.  People are drawn to light, they can also despise light if it sheds light on their dark deeds.  In both cases the one who lets their light shine will eventually become exhausted and weary, perhaps even discouraged and alone.  This is why we need daily vigilance and prayer.  "Watch and pray," Christ tells us continuously.  Watch that your speech and actions are synchronized with your heart and mind.  Pray so that you may receive from Jesus the consolation others take from you.

The daily discipline of keeping a bit in one's mouth (and writing) may seem very difficult.  In fact we are warned it will be a battle against ourselves.  "The violent take the Kingdom of Heaven by force."  (Matthew 11.12)  "The Kingdom of Heaven does not belong to those who sleep and who indulge all their desires, but to those who fight against themselves."  (Clement of Alexandria, Quis dives salvetur, 21)