Now I exhort you, brethren, by the name of our Lord Jesus Christ, that you all agree and that there be no divisions among you, but that you be made complete in the same mind and in the same judgment.
Unity is a profound, even mystical quality.
Unanimity, on the other hand is very tidy. It can be measured, monitored, and enforced. It is largely external, whereas unity is essentially internal. Its primarily goal is correct behavior, while unity's is a right spirit. Unanimity insists on many orthodoxies in addition to those of belief and behavior, including orthodoxy of experience and vocabulary.