Note 1 at Rom. 15:22: The cause that Paul is referring to is his desire to preach the gospel to everyone who had not heard. He had wanted to go to Rome, but he felt it was necessary to preach the gospel to everyone in the areas he had already been first. This is what he refers to in the next verse when he says, "now having no more place in these parts." He was saying there was no place left in those parts that hadn't heard the gospel. Therefore, he was ready to depart for new, unreached areas.