Animal Farm is an allegory of the Bolshevik revolution. Moses represents the Russian Orthodox Church (he might also represent Rasputin). Napoleon represents Joseph Stalin. Toward the end of Stalin's reign he needed the church on his side in an effort to try and hold onto his power. Napoleon allowed Moses to return because he was telling the animals about Sugar Candy Mountain, a place like heaven for animals. The pigs tell the animals that he's wrong, yet they pay him in beer to stay. They want the old and weak animals to go quietly when it's their time to go.
moses ir representing george orwells views on religion. he spread all these ideas to the animals and neighbouring farm, he also uses propaganda. just like how churches use propaganda