Paul is trying to make sure that thay don't think he is after more money, but at the same time is appreciative of all the help thay have given him. Indeed, at one time they were the only ones who did help him. And this had been no isolated case, they continued to help him. Then we get another asssurance that he is not looking for more. Instead Paul is looking for an increase in their fruit. This is both in their personal growth and in the further growth of the gospel.
Paul has already received their gift and is amply supplied. Moreover, he assures them that their gift is pleasing in God's sight as well. Just as Paul knows God's provision, he assuresbthem that they too will know His abundant provision. God provides according to His riches in glory in Christ. Now some take this too mean that we will get more money. Sometimes we wil, but this an impoverished way of looking at it. God's riches go way beyond this. It means we will always be able to be successful in advancing the kingdom. So it is to God that the glory belongs, always.
Paul closes with a final greeting.