Romans 15:22

22.And on this account, etc. What he had said of his apostleship he applies now to another point, even for the purpose of excusing himself for not having come to them, though he was destined for them as well as for others. He, in passing, then intimates, that in propagating the gospel from Judea as far as to Illyricum, he performed, as it were, a certain course enjoined him by the Lord; which being accomplished, he purposed not to neglect them. And lest they should yet think that they had been neglected, he removes this suspicion by testifying, that there had been for a long time no want of desire. Hence, that he had not done this sooner was owing to a just impediment: he now gives them a hope, as soon as his calling allowed him.

From this passage is drawn a weak argument respecting his going to Spain. It does not indeed immediately follow that he performed this journey, because he intended it: for he speaks only of hope, in which he, as other faithful men, might have been sometimes frustrated. (459)