Paul begins Romans 9 with a very emotional statement of passion for his people, the Jews. Paul says that he has great sorrow and unceasing anguish in his heart for his people. He says that he wishes he could give up his salvation so that they could be saved (Rom 9.2-3). He says a little later on that his heart's desire and his prayer is that they would be saved (Rom 10.1). What a passion for souls!
Interestingly, Paul's passion for people is guided by a recognition that not everybody is going to be saved. In the middle of these two verses, Paul tells us that God hardens some people towards salvation, while also softening some people in order to receive Jesus. God has mercy on whomever He wills and He hardens whomever He wills (Rom 9.18).
At first, these two paragraphs seem in contradiction to one another. It seems that Paul should either really passionate to see people saved or quietly confident that whoever will get saved will get saved. But, he's not. He is both passionate and trusting in God's truth.
I need to grow in both passion and truth. I need to be more passionate for people, more desirous to see people saved, and more eager to share the gospel with a dying world. I also need to be more confident that God will soften people's hearts, that salvation rests with Him, and that He is glorified even in the gospel being rejected.
If I get out of balance, passionate with too little truth, I'll end up acting as if salvation is something that I can do for someone. I'll try to do the work of the Holy Spirit myself. I'll think that just one more verse, or one more conversation, or one more new book will save that lost person. I'll think that salvation is the ultimate end of all things, not God's glory.
If I get out of balance, truth with too little passion, I'll rarely witness or pray. I'll rarely witness, because I'll think "well, they'll get saved anyway." I'll rarely pray, because God already knows and He'll save whomever He wills. I will become an ineffective Christian.
The key is keeping both passion and truth in balance, while also growing in them both.
More passion. More truth. To God be the glory.