Some translations set quotations from the Old Testament farther to the right on the page than the rest of the text. The ULB does this with the quoted material in 23:5.
This is a common metaphor in Scripture for those who appear righteous but are not. (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/tw/dict/bible/kt/righteous]])
The Pharisees believed that, after death, people would be risen from the dead for punishment or reward. The Sadducees did not share this belief. They only trusted in the physical world. (See: [[rc://en/tw/dict/bible/other/raise]] and [[rc://en/tw/dict/bible/other/reward]])
Some Jews made a promise to God that they would not eat or drink until they killed Paul, and asked God to curse them if they did not follow their promise. This is not something that would have pleased God, and they were clearly wrong for doing this. It is ironic that they used a holy vow in such an unholy way. (See: [[rc://en/tw/dict/bible/kt/curse]], [[rc://en/ta/man/translate/figs-irony]], [[rc://en/tw/dict/bible/kt/holy]], [[rc://en/tw/dict/bible/kt/vow]] and [[rc://en/tw/dict/bible/kt/holy]])
Men who had Roman citizenship were given many privileges. For example, they could appeal to Caesar if they were accused of a crime. Having Roman citizenship was very valuable and people would go to great lengths to attain citizenship. This "chief captain" could have gotten into trouble for treating a Roman citizen in this way.