LEARN KOREAN (한국어) [GRAMMAR] #1

DO SOMETHING FOR SOMEBODY: ~을/를 위해(서)

If you want to say that you are doing something FOR (the benefit of) somebody, you can add ~를/을 to the person who you are doing something for, followed by 위해(서):

나는 나의 여자 친구를 위해(서) 꽃을 샀어 - I bought flowers for my girlfriend
나는 부장님을 위해(서) 이것을 썼어 - I wrote this for my boss
저는 친구를 위해 빵을 만들었어요 - I made bread for my friend

There doesn't seem to be a difference between 위해 and 위해서.

This form is usually used when you are doing something for a person, but can also be used sometimes when you are doing something for a non-person:

저는 회사를 위해 열심히 일할 거예요 - I will work hard for the company

The important thing is that the thing for which you are doing something must be a noun. You can use 위해 to indicate that you are doing something for the purpose of a verb (I am going there to/for the purpose of see(ing) a movie) but you will learn about that once you have learned how to change verbs into nouns.

Also make sure that you realize that 'for' can have many meanings in English. Just because you say 'for' in English, doesn't mean that it can be translated directly to ~를/을 위해. In Korean, ~를/을 위해 means for the benefit of. For example, in this sentence:

I am waiting for the bus – the 'bus' is the object which you are waiting for, so, in Korean, you attach the particle ~을/를 to 'bus' but not ~을/를 위해:

나는 버스를 기다린다

This isn't incredibly important right now, but I thought I'd mention it. "위해" is actually a verb, and the base form of the verb is 위하다. When ~아/어/여 is added to 위하다, it changes to 위하여. 하다 officially changes to 하여 when adding ~아/어/여, but this is commonly shortened to 해. Therefore, it is possible to use "위하여" instead of "위해." Technically, this is possible in any word that finishes in ~하다, but it seems to be much more common with 위하다 than any other verb or adjective.