A religious father put safety pins through the tongues and lips of his two children and slit their mouths with scalpel blades, a court has heard.
The father, from Nigeria, told the boys he inflicted the injuries because God had his tongue cut off in the Bible, a jury at Bradford Crown Court was told.
The Bradford man, who cannot be named, denies charges of unlawful wounding and cruelty between 2003 and 2005.
The boys' mother also denies charges of cruelty during the same period.
Caroline Wigin, prosecuting, said the mother would watch, or turn a blind eye, as the father carried out the injuries.
The boys' injuries were discovered in February 2005 when a school friend of the older boy, now aged 13, noticed bruises on his body during a PE lesson, the court heard.
Miss Wigin said the boy told a learning mentor that his father beat him five to six times a week.
The boy's younger brother, now aged 11, was questioned and told the school he had been assaulted the previous night when his father swung a pole at him, causing cuts to his fingers.
A medical examination revealed injuries consistent with the boys' stories, Miss Wigin said.
The boys were subsequently placed with foster carers.
Miss Wigin said: "[The older boy] told his foster carer how safety pins had been put through their top lips, tongue and bottom lip, then they had to sit still and not move.
"A scalpel had been used to slit their lips and inside their mouths. Their father had then sewn them up with a medical kit that he had."
Miss Wigin added that the boy said his father "spoke about God in the Bible having his tongue cut off" as an explanation for why he carried out the injuries.
When interviewed, both parents, who have two other children, denied the boys suffered any serious injuries.
The trial continues.