John Calvin Commentary Romans 15:22

"Wherefore also I was hindered these many times from coming to you:" — Romans 15:22 (ASV)

And on this account, etc. What he had said about his apostleship he now applies to another point, for the purpose of excusing himself for not having come to them, though he was destined for them as well as for others. He then, in passing, intimates that in propagating the gospel from Judea as far as Illyricum, he performed, as it were, a particular course enjoined on him by the Lord; once this was accomplished, he intended not to neglect them.

And so that they would not still think they had been neglected, he removes this suspicion by testifying that for a long time there had been no lack of desire on his part. Therefore, the fact that he had not come to them sooner was due to a legitimate obstacle; he now gives them hope of doing so as soon as his calling permitted.

From this passage, a weak argument is drawn regarding his going to Spain. It does not, in fact, immediately follow that he made this journey because he intended it, for he speaks only of hope, in which he, like other faithful men, might sometimes have been frustrated.