From the Texas declaration of causes, right after the preamble:
Texas abandoned her separate national existence and consented to become one of the Confederated States to promote her welfare, insure domestic tranquility and secure more substantially the blessings of peace and liberty to her people. She was received into the confederacy with her own constitution, under the guarantee of the federal constitution and the compact of annexation, that she should enjoy these blessings. She was received as a commonwealth holding, maintaining and protecting the institution known as negro slavery — the servitude of the African to the white race within her limits — a relation that had existed from the first settlement of her wilderness by the white race, and which her people intended should exist in all future time. Her institutions and geographical position established the strongest ties between her and other slave-holding States of the confederacy. Those ties have been strengthened by association. But what has been the course of the government of the United States, and of the people and authorities of the non-slave-holding States, since our connection with them? … In all the non-slave-holding States, in violation of that good faith and comity which should exist between entirely distinct nations, the people have formed themselves into a great sectional party, now strong enough in numbers to control the affairs of each of those States, based upon the unnatural feeling of hostility to these Southern States and their beneficent and patriarchal system of African slavery, proclaiming the debasing doctrine of the equality of all men, irrespective of race or color–a doctrine at war with nature, in opposition to the experience of mankind, and in violation of the plainest revelations of the Divine Law. They demand the abolition of negro slavery throughout the confederacy, the recognition of political equality between the white and the negro races, and avow their determination to press on their crusade against us, so long as a negro slave remains in these States.