The gospel teaches us to love God and others (v.9 – 10a)
God, whom I serve with my whole heart in preaching the gospel of his Son, is my witness how constantly I remember you 10in my prayers at all times; NIV
The Apostle Paul has already poured out his heart in the preceding verse in thanks to God for the Roman believers. Here, he continues in that line to emphasize his relationship with the Roman believers. Since Paul had not yet been to Rome at this time (v. 10b), he probably had not met the majority of believers in Rome. But the Apostle knows one or two sure ways in which he is related to the Roman believers.