1)
Verse 4 already requested this! Why is this repeated?
1.
Rashi: Save us from Bnei Yavan.
2.
Radak: It is common for one who prays to repeat his words to strengthen the request. There is a small change in the repetitions.
3.
Malbim: Because our enemies mock our neighbors for quarreling with a lowly nation like us (verse 7), return us to our former grandeur and wealth!