What was Titus's role in collecting the offering for the poor saints?
Titus was to finish the grace already begun among them and, taking up the Apostle Paul's mantle, to gather the offerings for the poor saints in person. He was entrusted with completing the collection, consistent with giving under grace as God prospered and laid it on believers' hearts.
Les explains that Paul and his companions desired Titus, who had begun the work, to finish in the Corinthians the same grace. Les says Titus was picking up the mantle from the Apostle Paul to gather these offerings for the poor saints in person. The context stresses that this giving was not by legal binding or regulations, but under grace: the saints gave as God prospered them and as the Lord laid it on their hearts, after first giving themselves to the Lord and opening themselves to Paul's ministry.
Insomuch that we desired Titus, that as he had begun, so he would also finish in you the same grace also.