The only requirement to be a Christian is to believe in the Resurrection and its purpose according to scripture. Anything else is just argumentative between sects of the religion.
I'd say even that is up for argument.
I'm sure many would claim that the message is more about how to live your life in the here and now. At least that's how I heard some say it, and that's how I choose to interpret the Pope's message.
PS: oof, I just realized that you differentiate between being Christian and living according to Jesus' message.