As if an only child

Mahamati, wherever there are sentient beings, let us cherish the thought of kinship with them, and thinking that all beings are to be loved as if they were our only child, let us refrain from exploiting and killing them.  

Bodhisattvas, whose nature is compassion, avoid consuming flesh. Even in exceptional circumstances, it is not compassionate for a Bodhisattva in good standing to eat flesh. 

—Buddha Shakyamuni, Lankavatara Sutra