I wonder if it's related to Ambalatthika-rahulovada Sutta
Ambalatthika-rahulovada Sutta wrote:
Having tossed away the little bit of left-over water, the Blessed One said to Ven. Rahula, "Rahula, do you see how this little bit of left-over water is tossed away?"
"Rahula, whatever there is of a contemplative in anyone who feels no shame at telling a deliberate lie is tossed away just like that."
Without complete honesty, it's very easy to lie to oneself about the motivations behind any other action and the harm it causes.