The Bible, Job 12:10
In [God's] hand is the soul of every living thing and the breath of all mankind.
Gary Kowalski, Unitarian Minister (1991)
No longer can we discount the lives of sensitive and intelligent creatures, merely, because they assume nonhuman form...Animals, like us, are living souls. They are not things. They are not objects.
St. John of the Cross, Spiritual Canticle (1582)
All the creatures—not the higher creatures alone, but also the lower, according to that which each of them has received in itself from God—each one raises its voice in testimony to that which God is...each one after its manner exalts God, since it has God in itself.
Sefer Ha Chinuch, Mitzvah 596.
When a man becomes accustomed to have pity upon animals...his soul will likewise grow accustomed to be kind to human beings.
St Catherine of Genoa, The Spiritual Dialogue (1497)
All goodness is a participation in God and His love for His creatures. God loves irrational creatures and His love provides for them.
The Monks of New Skete Monastery, Cambridge, NY (1978)
The monastic fathers interpreted this [affinity with animals] as an illustration of the monk’s task to help restore the order that existed in Paradise, where man and beast, and indeed, all creation, lived in Harmony.
Charles Skriver, Evangelical Lutheran Minister (1977)
Inside the [Christian] churches they still doubt whether animals have an immortal soul. They hold to this ignorance in order to be able to commit unscrupulous violence towards animals.