I recently received this question in an email:

While it is true the proscription against torture can be nowhere found in the Book, we can also say that nowhere is doctrine of the Trinity explicitly spelled out. But this is an argument from silence, which says that because a text is silent on an issue, it has nothing to say to the issue.

But this argument from silence ignores the whole testimony of Scripture as to the expected character of the righteous man.

I would find it extremely ironic that the same God who instructs the righteous to care for animals would not expect us to extend similar care for prisoners (Proverbs 12:10, Deuteronomy 22:4, Exodus 23:5, Deuteronomy 25:4).