Why did Sam Houston refuse to take an oath of allegiance to the confederate states of America?

Sam Houston refused to take an oath of allegiance to the Confederate States of America because he believed in the preservation of the Union and opposed secession. As a former governor of Texas and a strong supporter of the Union, he felt that the Confederacy was leading the nation towards division and conflict. Houston's commitment to his principles and his belief in the importance of national unity ultimately led to his political downfall in Texas.