He also said God would visit "sickness and death" on those involved if his trial wasn't immediately stopped,
which brought a stern rebuke from the judge.
Warren Jeffs, 55, is facing a maximum sentence of life in prison if convicted of sexually assaulting two underage girls. After firing his high-powered lawyers Thursday, he made no opening statement and spent hours sitting alone at the defense table staring into space while prosecutors made their case.
On Friday, however, Jeffs suddenly cried, "I object!" as FBI agent John Broadway testified about seizing eight desktop computers and 120 boxes and large folders of documents from the church's remote compound in Eldorado in 2008.
"There is sacred trust given to religious leadership not to be touched by government agencies," Jeffs said.
He then launched into a lengthy defense of polygamy, but Walther eventually overruled his objection. She said court rules prohibit him from testifying while objecting, but she let him go on at length because he hadn't offered an opening statement.
Jeffs then said he had no choice but to read a statement from God. Walther dismissed the jury and allowed him to read it.
"I, the Lord God of heaven," Jeffs read, "call upon the court to cease this open prosecution against my pure, holy way."
If the trial continues, he read, "I will send a scourge upon the counties of prosecutorial zeal to make humbled by sickness and death."
Walther told Jeffs he could not threaten jurors.
"If you call for their destruction," she said, "or in any way say that they will be injured or damaged because of their service, you will be removed from the courtroom."
Jeff is the ecclesiastical head of the Fundamentalist Church of Jesus Christ of Latter Day Saints, an offshoot of mainstream Mormonism. The sect believes that polygamy brings exaltation in heaven, and its 10,000 members see Jeffs as a prophet who speaks for God on earth.
During afternoon testimony, Jeffs objected so often that Walther eventually had a bailiff remove his microphones.
All seven sect members prosecuted since the 2008 raid have been convicted and given prison terms ranging from six to 75 years.