God is just. All the time he is just. And he has made us to fulfil the purposes he has called us to fill. This passage isn’t exactly the easiest of them all to swallow. Chapter 9 reminds us that it is purely God’s will that saves, and follows up in chapter 10 with the need for evangelism. I was talking with someone about this recently, and how these two concepts match up. Yes, we are to evangelise, because if we don’t tell them, who will? But also, because it is God working through us, it is not upon us to save people. Tell, yes. But save, no. That rests on God and releases us from any anxiety that we did it wrong at the time.