Instead, whoever wants to become great among you must be your servant, and whoever wants to be first must be your slave
Jesus certainly had the service mentality. The ultimate service was for him to take human form and come to earth for us. He showed service mentality numerous times throughout the gospels. The apostles did not understand this. But, I think maybe when he insisted on washing their feet they finally “got it” or at least a little of it. Of course a central aspect of service is humility. We Christians should never think more highly of ourselves than others around us. We are all sinners and worthy of God’s wrath. It’s just a matter of degree. God is perfect and demands perfection of us. Of course none of us will ever get to that state but that doesn’t mean we shouldn’t at least try to do good while we are here.
I personally believe that a service mentality is at the very core of Christian belief. Another name for service is works. Here is what Martin Luther said about that in his preface to the book of Romans.
This it is impossible to separate works from faith, quite as impossible as to separate heat and light from the fire.