The Quran Verse
Surah 12:26–27:
He [Joseph] said, 'It was she who sought to seduce me.' And a witness from her family testified. 'If his shirt is torn from the front, then she has told the truth... But if his shirt is torn from the back, then she has lied...'
The Relevant Source Text (The Bible vs. Folklore)
Genesis 39:12:
She caught him by his garment, saying, 'Lie with me.' But he left his garment in her hand and fled and got out of the house.
In Genesis, there is NO "forensic" debate about the shirt; Potiphar simply believes his wife. The Quranic version introduces a sophisticated legal argument about the direction of the tear.
Critics argue this was added to provide a more "logical" or "legalistic" flow to the story, mirroring the Arabian preoccupation with tribal arbitration and evidence.
It moves away from the biblical theme of Joseph's suffering and God's providence toward a theme of human cleverness and vindication.