Midrasch zu Wajikra 24:19

3) (Vayikra 24:19) ("And a man, if he inflicts an injury upon his neighbor; as he did, so shall it be done to him.") "And a man, if he inflicts an injury upon his neighbor": This tells me only of an (actual) injury). Whence do I derive (that the same halachah applies) if he screamed in one's ear, tore one's hair, spat at someone and hit him with his spittle, pulled off someone's garment, or uncovered a woman's head in the market place? From "as he did" (though no actual injury was inflicted), so shall it be done to him."

4) And whence is it derived (that the same applies) if he hit him with the back of his hand, with a tablet, with a board, or with a roll of papers in his hand? From "as he did, etc."

5) Whence is it derived that if he took hold of him and placed him in the sun, so that he was overcome by heat, or in the cold so that he was chilled, or if he held a dog or a snake to bite him? From "as he did, etc."