Some translations set each line of poetry farther to the right than the rest of the text to make it easier to read. The ULB does this with verses 7-8 of this chapter, which are words from the Old Testament.
Paul builds upon material from chapter 3. He explains how Abraham, the father of Israel, was justified. Even Abraham could not be justified by what he did. Obeying the law of Moses does not make a person right with God. It is a way a person shows they believe in God. People have always been justified only by faith. (See: [[rc://en/tw/dict/bible/kt/justify]], [[rc://en/tw/dict/bible/kt/lawofmoses]] and [[rc://en/tw/dict/bible/kt/faith]])
Circumcision was important to the Israelites. It identified a person as a descendant of Abraham. It was also a sign of the covenant between Abraham and Yahweh. However, no person was justified only by being circumcised. (See: [[rc://en/tw/dict/bible/kt/circumcise]] and [[rc://en/tw/dict/bible/kt/covenant]])
Paul frequently uses rhetorical questions in this chapter. It appears the intent of these rhetorical questions is to make the reader see their sin so they will trust in Jesus. (See: [[rc://en/ta/man/translate/figs-rquestion]], [[rc://en/tw/dict/bible/kt/guilt]] and [[rc://en/tw/dict/bible/kt/sin]])