en_tn/rom/09/33.md

as it has been written

You can indicate that Isaiah wrote this. You can also translate it in an active form. AT: "as Isaiah the prophet wrote" (See: rc://en/ta/man/translate/figs-explicit and rc://en/ta/man/translate/figs-activepassive)

in Zion

Here Zion is a metonym that represents Israel. AT: "in Israel" (See: rc://en/ta/man/translate/figs-metonymy)

stone of stumbling and a rock of offense

Both of these phrases mean basically the same thing and are metaphors that refer to Jesus and his death on the cross. It was as if the people stumbled over a stone because they were disgusted when they considered Jesus' death on the cross. (See: rc://en/ta/man/translate/figs-doublet and rc://en/ta/man/translate/figs-metaphor)

believes in it

Because the stone stands for a person, you may need to translate "believes in him."