Note 6 at Ac 21:24: To "be at charges with them" simply means that Paul bore the expenses of their vow. This was an attempt to witness to the Jews that he was not anti-Law, since he was performing a vow himself and supporting others who did the same.

According to the laws of the Nazarite vow (Nu 6:13-15), which it is supposed that Paul and these men were performing, the offerings that had to be made per person were two lambs, one ram, a basket of unleavened bread, cakes of flour and oil, wafers of unleavened bread anointed with oil, meat offerings, and drink offerings. At today's prices, this would amount to hundreds of dollars per person and thousands of dollars for this group of five.

Although Paul spoke of times when he was without natural resources (Php 4:12), we can see that this was not always the case. Paul had quite a bit of money, or he would not have been able to finance these men in this vow. If this money had been given to him by the elders of the church at Jerusalem, then it wouldn't have impressed anyone that he bore the expenses of this vow. Therefore, this is quite a statement of the financial condition that Paul operated in at least part of the time.

Note 7 at Ac 21:24: Paul did keep the Law. But his actions of holiness that fulfilled the commandments of the Law were the natural outflow of the relationship that he had with the Lord through faith, not as a way to it. Holiness is a fruit, not a root, of salvation (see note 1 at Mt 22:36 and note 21 at Mt 23:26).