The woman, in whose house he was staying, attempted to seduce him away from himself. She closed the doors and said, "I have prepared myself for you." He said, "I seek refuge with God, He is my Lord, He made good my residence; the wicked do not succeed."
Translation endnotes
[12:23] Joseph is using a statement with multiple meanings. The woman most likely understood it as a reference to her husband. In fact, Joseph, as a monotheist, could not have meant that; with the phrase "my Lord" he meant his Creator. Joseph cannot be referring to the person who purchased him as slave (12: 39,42,50; 6:164; 9:31).