I don't know why we use will because we don't know whether others will do what we ask or not. I wonder whether there is actually an omitted if-clause there.
Example 1:
May I borrow your notebooks? They will help me understand the subject more (if you lend me the notebooks).
Example 2:
You have to give me advice. Your advice will give me more background knowledge about what to major (if you give me advice).