"It's time again to revisit Rambo," Stallone told a news conference. "The other Rambo films have always been about some military quest or revisiting Vietnam ... but this time I was looking for subject matter that would take everyone on a spiritual quest to really explain what God means to people in other parts of the world," IGN Film Force reported.
Stallone explained the film is set among the Karen people of Myanmar, formerly Burma, a group that has been subjected to genocide for more than 50 years.
In the film, a group of Christian relief workers is captured and Rambo goes after them.
Stallone said he had become self-absorbed and made some poor decisions that led to a bum ending for the Rocky franchise, but he plans to change that with Rocky VI.
"I had gone through a lot of trials and tribulations in my own personal life -- a lot of ups and downs -- and I just felt as though I was being compelled to do something. It was like with the first movie -- I was a writer, but I've said it before... I felt as though God was moving me to do this," said Stallone.