It goes without saying

We use this expression to say that something is absolutely sure or completely normal or necessary.

You can use this phrase in ………… language.

 Spoken
 Written
 Formal
 Informal

Example 1
A: If you want to have a party at work, you’ll have to ask the boss for her permisson.
B: Of course. It goes without saying.

Example 2
A: Do you think you will be at John’s wedding? 
B: Of course. It goes without saying. We’ve been best friends for years.