Philippians 2:1-11 is really one argument, and it's this..."Gospel unity comes from gospel humility, which we learn from Christ's example". In verses 1-4, we are going to get to the first part of that argument: "Gospel unity comes from gospel humility".
Firstly, you can't get unity, or humility, without reflecting on and depending on the gospel. That's why Paul begins in verse 1 with his phrases "if any...if any...if any...if any". That's a gospel reflection. Those are the promises of the gospel. So why don't we 'get' (receive, have) unity? Because we don't 'get' (understand, reflect and depend on) the gospel! That's why of Paul's 4 phrases in v. 2, he says "have the same mind" twice (1st and 4th)... because this is about how we think about life. We need Christ and His gospel to control our thinking.
Secondly, this gospel thinking should lead us to be humble. Humility is a big concept in the bible, but Paul's simple reasoning here is that we can't be concerned with our own reputation, honor, or importance ("selfish ambition" and "conceit"---this was the Roman attitude to life, not Christ's). Humility is the cure for the chief disease that threatens our unity...jealousy. Therefore, gospel humility means that a) God is using me to be concerned with the needs of others, and b) God desires that I would rejoice in the growth and gifts of others, and not just my own. Therefore, Gospel thinking will lead me to humility that sets my gaze on others' concerns. And next week, we'll see how Christ is our perfect example of that!