Tex. Government Code § 406.053: OATH.

Before performing the duties of office, a commissioner of deeds shall take and subscribe an oath to well and faithfully perform the duties of office under the laws of this state. The oath shall be:

(1) taken before the clerk of a court of record in the city, county, or country in which the commissioner resides;

(2) certified to by the clerk under the clerk's hand and seal of office; and

(3) filed in the office of the secretary of state of this state.

Acts 1987, 70th Leg., ch. 147, Sec. 1, eff. Sept. 1, 1987.