O ye who believe! be strict in observing justice, and be witnesses for Allah, even though it be against yourselves or against parents and kindred. Whether he be rich or poor, Allah is more regardful of them both than you are. Therefore follow not low desires so that you may be able to act equitably. And if you conceal the truth or evade it, then remember that Allah is well aware of what you do.
Islam, the Holy Qur’an,4:136
You must be truthful. Verily, truthfulness leads to righteousness and righteousness leads to paradise. A man continues to be truthful and encourages honesty until he is recorded with Allah as truthful. And beware of falsehood. Verily, falsehood leads to wickedness and wickedness leads to the hellfire. A man continues to tell lies and encourages falsehood until he is recorded with Allah as a liar.
Islam, the Holy Prophet (sa), Hadith of Sahih Muslim
Qawl e Sadeed (the right word) entails uttering what is completely true and appropriate and has no hint of randomness, uselessness and falsehood.O you who believe, fear God and say what is based on truth, honesty, fairness and wisdom. Do not talk randomly and speak at the right time and place.
Islam, The Promised Messiah (as), Translated from Tafseer Holy Qur’an, Vol. III, p. 731–732
Putting away falsehood, let everyone speak the truth with his neighbour, for we are members one of another.
Christianity, The Bible, Ephesians4:25
One should utter the truth.
It is always proper to speak the truth. It is better again to speak what is beneficial than to speak what is true. I hold that this is the truth which is fraught with the greatest benefit to all creatures.
Hinduism, Mahabharata, Shanti Parva, 329:13
When a man vows a vow to the Lord or swears an oath to bind himself by a pledge, he shall not break his word; he shall do according to all that proceeds from his mouth.
Judaism, Tanakh, Numbers, 30:2