Androcles, a fugitive Christian tailor, accompanied by his nagging wife, is on the run from his Roman persecutors. While hiding in the forest he comes upon a wild lion who approaches him with a wounded paw. His wife runs off. Androcles sees that the cause of the animal's distress is a large thorn embedded in its paw, which he draws out while soothing the lion in baby language.
Androcles is captured and is sent to the Colosseum to be executed with other Christians in gladiatorial combat. They are joined by a new Christian convert called Ferrovius, who struggles to reconcile his Christian principles with his violent inclinations. The Roman captain guarding them is attracted to the genteel convert Lavinia. Eventually the Christians are sent into the arena, but Ferrovius kills all the gladiators before they can harm any Christians. He is offered a job in the Praetorian Guard, which he takes. The Christians are to be released, but the crowd demands blood. To satisfy them, Androcles offers himself to be savaged by lions. But the lion that is supposed to kill him turns out to be the one that Androcles saved, and the two dance around the arena to the delight of the crowd. The emperor comes into the arena to get a closer look, and the lion attacks him. Androcles calls him off and the emperor is saved. He then declares an end to the persecution of Christians. Androcles and his new 'pet' depart together.

Question: Why doesn't the lion attack Androcles?
Answer: It's the same lion that Androcles removed a thorn from his paw
Alternative answer: He helped the lion prior to being placed in the arena with it