The Jataka, Vol. III, tr. by H.T. Francis and R.A. Neil, , at sacred-texts.com
"Who got his friend," etc.—This was a story told by the Master, whilst living in the Bamboo Grove, in reference to a saying that Devadatta could not even inspire alarm.
When Brahmadatta was reigning in Benares, the Bodhisatta was born in the family of a village householder, and when he was young he played with other boys at the foot of a banyan tree, at the entrance of the village. A poor old doctor at that time who had no practice strayed out of the village to this spot, and saw a snake asleep in the fork of a tree, with its head tucked in. He thought, "There is nothing to be got in the village. I will cajole these boys and make the snake bite them, and then I shall get somewhat for curing them." So he said to the Bodhisatta, "If you were to see a young hedgehog, would you seize it?" "Yes, I would," said he.
 "See, here is one lying in the fork of this tree," said the old man.
The Bodhisatta, not knowing it was a snake, climbed up the tree and seized it by the neck, but when he found it was a snake, he did not allow
it to turn upon him, but getting a good grip of it, he hastily flung it from him. It fell on the neck of the old doctor, and coiling round him, it bit him so severely 1 that its teeth met in his flesh and the old man fell down dead on the spot, and the snake made its escape. People gathered together about him, and the Great Being, in expounding the Law to the assembled multitude, repeated these verses:
A deadly snake, as hedgehog, if you please,
By the snake's bite was killed
As one that evil to his neighbour willed.
He that to strike is fain
The man that never striketh back again,
Is struck and lieth low,
E’en as this knave sore hurt by deadly blow.
So dust that should be thrown
Against the wind, back in one's face is blown;
And ill designed to one
That holy is, and has no evil done,
On the fool's pate at last
Recoils, like dust when thrown against the blast.
The Master here ended his lesson and identified the Birth: "At that time the poor old doctor was Devadatta, the wise youth was myself."