[Witness] is a modest word saying what is there, honestly testifying to exactly what we see, what we hear. But when we enlist in a cause, it is almost impossible to do it right: we embellish, we fill in the blanks, we varnish the dull passages, we gild the lily just a little to hold the attention of our auditors... Important things are at stake -- God, salvation -- and we want so much to involve outsiders in these awesome realities that we leave the humble ground of witness and use our words to influence and motivate, to advertise and publicize. Then we are no longer witnesses, but lawyers arguing the case, not always with scrupulous attention to detail. 

Eugene Peterson. THE CONTEMPLATIVE PASTOR: RETURNING TO THE ART OF SPIRITUAL DIRECTION.