Paul had just made it through an uproar in Ephesus and was leaving to raise funds for the poor church in Jerusalem.  Paul's commitment was immense tor the church and it was evident throughout his ministry.  He was committed to serve the churches that he ministered to by being a servant to them, Phil.1:1.  He certainly loved the churches and was willing to give of all of his resources including his life, 1Cor.11:22-29.  Paul was committed to teach the churches and in our passage he even did it all night.