A faithful witness will not lie.
A true witness
Truth is beautiful, as well as safe and mighty. In the incident related below a boy twelve years old, with only truth as a weapon, conquered a smart and shrewd lawyer, who was fighting for a bad cause. “Truth is the highest thing that man may keep,” and the noblest child or man is he that keeps the truth ever between his lips. Walter was the important witness in a lawsuit. One of the lawyers, after cross-questioning him severely, said, “Your father has been talking to you and telling you how to testify, hasn’t he? Yes,” said the boy. “Now,” said the lawyer, “just tell us how your father told you to testify.” “Well,” said the boy modestly, “father told me that the lawyers would try and tangle me in my testimony; but if I would just be careful and tell the truth, I could tell the same thing every time.” The lawyer didn’t try to tangle that boy any more. (The Fireside News.)
Falsehood and flaw
What a flaw is in steel, what a foreign substance is in any texture, that a falsehood is to the character, a source of weakness, a point where under strain it may break. (Newman Smyth.)