"No religious test shall ever be required as a qualification to any office . . . provided he acknowledge the existence of a Supreme Being." (caps per source). Article 1 Section 4 of the Texas state constitution - the "Bill of Rights".
I have lived in Texas off and on for my entire life, and it is by and large an ignorant redneck state. If it weren't for all of the people moving here from other states for the last 30 years or so, it would just be a giant Alabama. It is changing, but not fast enough.