What is the difference between なる　ｖｓ　なす?


While I have seen なる being used a lot, that is not so for なす。 What is the
usage of なす? The two have similar meaning which in its most simplest form
means "to become" i.e change in state of something.

Now here is a line, that I am having trouble dissecting:

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    大いなることをなすには犠牲は付き物だ。
    
[/code]

It uses なる、then なす then it uses は twice. It appear to be rather strange from
grammatical perspective.




なす(成す) is a verb and it has several meanings, as you can see in
[デジタル大辞泉](https://dictionary.goo.ne.jp/jn/164006/meaning/m0u/%E3%81%AA%E3%81%99/).  
This なす means "to achieve (a great thing)". No 2 in the dictionary.

大いなる is an adnominal adjective which means "great" but a little old‐fashioned
word, so 大いなることをなす means "To achieve a great thing".

