On treatment of animals and our responsibility:
“It is not only their fellow human beings that the beloved of God must treat with mercy and compassion, rather must they show forth the utmost loving-kindness to every living creature. For in all physical respects, and where the animal spirit is concerned, the selfsame feelings are shared by animal and man. Man hath not grasped this truth, however, and he believeth that physical sensations are confined to human beings, wherefore is he unjust to the animals, and cruel. And yet in truth, what difference is there when it cometh to physical sensations? The feelings are one and the same, whether ye inflict pain on man or on beast. There is no difference here whatever. And indeed ye do worse to harm an animal, for man hath a language, he can lodge a complaint, he can cry out and moan; if injured he can have recourse to the authorities and these will protect him from his aggressor. But the hapless beast is mute, able neither to express its hurt nor take its case to the authorities … Therefore it is essential that ye show forth the utmost consideration to the animal, and that ye be even kinder to him than to your fellow man. Train your children from their earliest days to be infinitely tender and loving to animals. If an animal be sick, let them try to heal it, if it be hungry, let them feed it, if thirsty, let them quench its thirst, if weary, let them see that it rests.”
Selections from the Writings of ‘Abdu’l-Bahá, complied by the Universal House of Justice, Bahá’í Publishing Trust, Wilmette, 1996, p. 167