Living Grounded: talking to people about truth, Mark 10:40 & unity with gospel-centred churches?

Questions:

1. How can I share my faith in Jesus and the truth of the Gospel with others who see it as just one subjective truth among many, while showing that it is the objective truth, without causing division or harming relationships? b) How do we witness to people who don’t see the bible as authoritative? What can we appeal to if they reject the Bible wholesale?

2. Who is Jesus talking about in Mark 10:40 when he rebuked James and John for asking to sit at his right hand? 

3. During your response last week to unity you mentioned partnering with gospel centred churches. What does gospel centred mean? What is an example of not being gospel centred? I think it’s obvious that a Mormon or JW even Catholic is not gospel centred. I’m more interested in would we be able to say that the Uniting Church is gospel centred or the Pentecostal church would each church be case by case? What are the distinctives/ boundary lines that makes a church gospel centred or not?