Texas state prosecutors wrapped up their case against Jeffs by using his own words against him: a disturbing August 2006 audio recording of what Jeffs' called a "heavenly comfort" training session with three of his so-called "spiritual wives."
Earlier, lead prosecutor Eric Nichols gave an impassioned closing argument as he summarized the evidence for the jury, occasionally jabbing his finger toward Jeffs. He urged them to convict Jeffs, who he said cast sexual acts in terms of religious principals.
One of the females was exactly 12 years, one month, and three days old when the recording was made. Jeffs was charged with aggravated sexual assault for this incident, considered a first-degree felony.
Sexual contact with his wives, Jeffs believes, revives him spiritually and brings the girls closer to God.
The recording was made at the Yearning for Zion ranch in Texas, owned by the FLDS. It begins with Jeffs asking the girl how she feels.
"Feels good," she responds, according to a copy of the transcript reviewed by ABC News.
"Everyone else let go of me, back away a little" Jeffs says soon after. "Please get on the other side of the bed."
"You shall learn the powers of the spirit of God as a heavenly wife should," Jeffs tells the 12-year-old. "Let the heavenly comfort hear us."
"We bless you, by the Lord, at this young age. To come to know God and his power, and feel his presence," says Jeffs, according to the transcript.
Throughout the 20-minute tape, there are periods where sounds described by the transcript as "rhythmic heavy breathing" can be heard.
At one point, Jeffs again asks the girl how she feels.
"I feel fine, thank you," she says.
Jeffs later tells a woman in the room to "face her" -- an apparent reference to the 12-year old. He is also heard saying, "want to distract her."
As the session ends, Jeffs begins to pray.
"Behold father these three ladies, innocent and pure," he says. "We thank you for these gifts and join in a prayer of oneness."
Then, Jeffs addresses the 12-year old.
"Come give me a hug," Jeffs says.
Texas Ranger Nick Hanna testified the recording was found when Jeffs was arrested during a traffic stop in Nevada a few weeks later. Another copy was found at the Yearning for Zion ranch when it was raided in 2008.
Jeffs' sect broke off from the mainstream Mormon Church 72 years ago. His 10,000 followers across North America consider him a prophet who serves as God's spokesman on Earth.
ABC News producer Gina Sunseri contributed to this report.