9:1 I am speaking the truth in Christ—I am not lying; my conscience bears me witness in the Holy Spirit— 2 that I have great sorrow and unceasing anguish in my heart. 3 For I could wish that I myself were accursed and cut off from Christ for the sake of my brothers,  my kinsmen according to the flesh. 4 They are Israelites, and to them belong the adoption, the glory, the covenants, the giving of the law, the worship, and the promises. 5 To them belong the patriarchs, and from their race, according to the flesh, is the Christ who is God over all, blessed forever. Amen. (Romans 9:1-5 (ESV)
“For I could wish that I myself were accursed and cut off from Christ for the sake of my brothers.”
Here Paul is echoing the sentiments of Moses who made a very similar appeal on behalf of the Israelites in the desert when they had broken with God’s covenant and kindled his anger. Paul could wish, that is to an extent Paul does wish, but he knows this is not God’s will. But it shows from where Paul’s missionary zeal comes from, it is an outgrowth of love.
Christian missionaries and evangelists love the people to whom they are sent it is why they go to them with the gospel. So it is bothersome today that people think it is an unloving thing to evangelize Jews, or Muslims, or anyone else for that matter. This also shows that Paul would vehemently disagree with those who think Jews are saved in any other way than gentiles are, in any other way than through faith in Jesus Christ and his atoning sacrifice.
Paul here goes on to enumerate the reasons Christians should love Jews. He notes that everything we have as Christians was given to us through the Jews, even our worship. It’s funny, but I don’t think enough attention is given to this passage when the topic of worship comes up. Paul uses a definite article concerning worship, though the Greek reads liturgy. It shows that in Paul’s day Christian worship was very similar to Jewish worship. It wasn’t a free for all orgy of ecstatic emotion. But the stayed, structured worship of the synagogues and temples, that could break out in song and joy, but also conveyed the seriousness of being in the presence of God with ceremony. It would only be natural that the early Christians would worship with the forms that Christ himself used when as was his custom he went to the Synagogue on the Sabbath. Perhaps that is a legalist way of looking at the question, and yet if Christ himself was enriched and strengthened by such worship, then perhaps it is something to consider. Over the years there have been many different “liturgies” and changes made to “the” liturgy, and yet the content and structure of liturgical worship has largely stayed the same as that which we have in our hymnals today. It reflects a communion of saints that predates even the coming of Christ himself, and a worship he himself blessed.