John 14:29

29 I have told you now before it happens, so that when it does happen you will believe.

Read John 14:29 Using Other Translations

And now I have told you before it come to pass, that, when it is come to pass, ye might believe.
And now I have told you before it takes place, so that when it does take place you may believe.
I have told you these things before they happen so that when they do happen, you will believe.