Boyett v. State
In Boyett v. State, 692 S.W.2d 512, 515 (Tex. Crim. App. 1985), the Texas Court of Criminal Appeals held that a jury charge should "explicitly" instruct jurors that if they do not believe, or if they have reasonable doubt of, an accused's guilt of a greater offense, "they should acquit" the accused of the greater offense and "proceed to consider whether the accused is guilty of a lesser-included offense." Id.
Furthermore, the Boyett court stated that it is best "to instruct the jury that if it has a reasonable doubt as to whether a defendant is guilty of any offense defined in the charge, it will find the defendant not guilty" and that this instruction should be located "after the last lesser included offense in the charge." Id. at 516.