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 the poetry that is quoted from the Old Testament in 4:27.
This is a complex issue discussed in this chapter. Scholars have many views on the issue of Israel's sonship. Not all of Abraham's physical descendants inherit the promises of Abraham. Only the children of Abraham, through his sons Isaac and Jacob, can inherit those promises and only those who follow him spiritually. It is through their faith that they become adopted into the family as sons with an inheritance ("children of promise"). (See: [[rc://en/tw/dict/bible/kt/inherit]], [[rc://en/tw/dict/bible/kt/promise]], [[rc://en/tw/dict/bible/kt/spirit]], [[rc://en/tw/dict/bible/kt/faith]] and [[rc://en/tw/dict/bible/kt/adoption]])
#### Other possible translation difficulties in this chapter ####
Abba is an Aramaic word. It was an informal way to refer to a person's father in ancient Israel. Paul "transliterates" its sounds by writing it with Greek letters.