"Man is no different from animals," says Sri Sankara Bhagavatpada in his
Sutrabhasya. "Pasvadibhiscavisesat".
Texts tell us: "Human beings and animals have the same urges. They eat and
sleep and copulate and besides, the feelings of fear are common to both.
What, then, is the difference between the two? It is adherence to
Dharma that distinguishes human beings from animals. Without Dharma
to guide him man would be no better than an animal."
"Aharanidrabhayamaithunam ca samanyametat pasubhirnaranam
Dharmo hi tesamadhiko visesah dharmena hina pasubhissamanah"
The Lord says in Bhagavad Gita: "When a man thinks of the objects of
sense, attachment to them is born; from attachment arises desire; and
from desire arises anger. Anger causes delusion and from delusion springs
loss of memory; loss of memory leads to the destruction of the sense of
discrimination; and because of the destruction of his sense of
discrimination man perishes."
Dhyayato visayan pumsah sangastesu pajayate
Sangat samjayate kamah kamat krodho bhijayate
Krodhad bhavati sammohah sammohat smrtivibhramah
Smrtibhramsad buddhinaso buddhinasat pranasyati
Commenting on these two slokas of the Gita, Swami Chinmayananda says
that evil develops from our wrong thinking or false imagination like a tree
developing from the seed. Thought has the power to create as well as to
destroy. Rightly harnessed, it can be used for constructive purposes; if
misused it will be the cause of our utter destruction. When our mind
constantly dwells on a "sense-object" an attachment is created for that
object. When we keep thinking of this object with increasing intensity,
our attachment to it becomes crystallized as burning desire for the same.
But as obstacles arise to the fulfilment of this desire, the force that at first
caused the desire now turns into anger.