Genesis 39

Joseph got into big trouble even though he was totally innocent:

 19 And it came to pass, when his master heard the words of his wife, which she spake unto him, saying, After this manner did thy servant to me; that his wrath was kindled.
 20 And Joseph’s master took him, and put him into the prison, a place where the king’s prisoners were bound: and he was there in the prison.

This part seems strange to me. It seems like Potiphar was overly lenient on Joesph. I would assume that he could have easily had Joseph put to death for so heinous an offense as trying to seduce his wife. It seems like any master who found a servant accused of that would have them immediately killed. And yet he let Joseph live.

My opinion is that Potiphar suspected his wife was perhaps not being truthful about this matter. I'm guessing that she was an unfaithful woman and that she had done this in the past with other men and I think her husband either knew that or suspected that or sensed that. I think that is why he put Joseph in prison instead of to death. I think he saw Joseph's purity in his countenance and I think he trusted in Joseph's character fully. And yet he had to do something. Here was an accusation from his own wife. Things would never be the same again. Joseph had to leave. And so I think he mercifully placed him in prison. But I think he knew Joseph was innocent or else I don't see any reason he would have let him live.