Harmful is all
false speech, lying, pretending, deceiving, & misleading!

Once in
Savatthi the Blessed
Buddha said this:
What, householder friends, is the Dhamma explanation befitting for oneself?
Here, householder friends, a Noble Disciple reflects thus: If someone were to
damage my welfare with false speech, lying, pretending, deceiving, &
misleading,
that would neither be pleasing nor agreeable to
me.
Similarly, if I were speak
false to, lie to, pretend, deceive, and mislead another being, that would
damage
that being's welfare & would neither be pleasing nor
agreeable nor acceptable
to that other being either....
What is displeasing and disagreeable to me, is also displeasing and
disagreeable
to any other being too. How can I harm & hurt another being with what provoke
annoy and exasperate myself? Having reflected repeatedly thus, then gradually:
1: He/she will carefully avoid all false speech, deception, and deceitfulness...
2: He/she will persuade others also to abstain from all false speech and lying...
3: He/she will praise speaking only honest, trustworthy, plain, straight Truth...
In this very way is this advantageous verbal behaviour purified in 3
respects!!

More on Not Deceiving
& Right Speech (Sammā Vācā):
http://www.accesstoinsight.org/ptf/samma-vaca.html
http://What-Buddha-Said.net/drops/Truth_Triumphs.htm
http://What-Buddha-Said.net/drops/IV/Not_Splitting.htm
http://What-Buddha-Said.net/drops/IV/Not_Scolding.htm
http://What-Buddha-Said.net/drops/IV/Not_Deceiving.htm
http://What-Buddha-Said.net/drops/IV/Not_Gossiping.htm
http://What-Buddha-Said.net/drops/What_is_Right_Speech.htm
http://What-Buddha-Said.net/drops/IV/Fourfold_Right_Speech.htm
http://What-Buddha-Said.net/drops/III/Optimal_Observance_IV.htm
You can run away from your mistake, but not
from your regret.
You can play with your drama, but not with your karma.
Theravada Buddhist Chaiteet
Heng, Malaysia
One
should never Harm other beings by
Deceiving them with
False Speech!
Source
(edited extract):
The
Grouped Sayings of the Buddha. Samyutta
Nikāya. [V:354-5]
section 55: Sotāpattisamyutta. Thread 7: To the people at the Bamboo gate...
Truth always Triumphs! from Bhikkhu Samahita on Vimeo.