There is a proverb in my language which says:
While there is big gap between now and the future and anything can happen in this time gap, so things can change in this period of time. Therefore, we should never be sure of our success or failure and we have to fight for it until the last second; because even when a good outcome or conclusion seems certain, things can still go wrong. (Encouraging) / (as an advice)
OR
We shouldn't lose our hope and think that everything has been finished already when an unplesant / bad outcome or conclusion seems certain, things can still go well and you might face a very desirable outome at the end! (Hopegiving)
In our language, we have two interchangeable proverbs for this case which can be used either in hopegiving situation or encouraging state:
1- Literal Translation: When you throw an apple up, it turns a hundred times before it come down.
The second equivalent proverb in my mother language which can work properly in this sense:
2- Literal Translation: From this column to that column may be a relief.
The only equivalent that I succeeded to find it is:
- There's many a slip twixt the cup and the lip.
But according to my researches, it sounds to be an archaic British proverb, whilst I'm looking for a proverb / expression in current AmE / BE.
I would appreciate it if you help me find the closest saying to the meaning in my question.