Texas Penal Code - PENAL § 6.01. Requirement of Voluntary Act or Omission

(a) A person commits an offense only if he voluntarily engages in conduct, including an act, an omission, or possession.

(b) Possession is a voluntary act if the possessor knowingly obtains or receives the thing possessed or is aware of his control of the thing for a sufficient time to permit him to terminate his control.

(c) A person who omits to perform an act does not commit an offense unless a law as defined by Section 1.07 provides that the omission is an offense or otherwise provides that he has a duty to perform the act.