John Calvin Commentary Acts 19:21

"Now after these things were ended, Paul purposed in the spirit, when he had passed through Macedonia and Achaia, to go to Jerusalem, saying, After I have been there, I must also see Rome." — Acts 19:21 (ASV)

He purposed in spirit. His meaning is that Paul purposed to take his journey through the prompting and guidance of the Spirit, so that we may know that his whole life was ordered according to God’s will and pleasure. And therefore, he had the Spirit as the governor of his actions, because he both surrendered himself to be ruled by Him and also depended upon His governance.

Nor does it matter that he did not have the success in his journey that he hoped for, for God often governs and rules His faithful servants, allowing them to be ignorant of the outcome. For He would have them be so completely devoted to Him that they follow what He has shown them by His Spirit, even shutting their eyes when matters are uncertain.

Moreover, it is certain that he was wholly devoted to benefiting the churches, omitting and neglecting his own convenience, since he would rather deprive himself of Timothy, who was to him most excellent of all, most faithful, most dear, and finally, a most fitting companion, rather than fail to provide for the Macedonians.