Reveal not every secret you have to a friend, for how can you tell but that friend may hereafter become and enemy. And bring not all mischief you are able to upon an enemy, for he may one day become your friend.
Wine is a turne-coate (first a friend, then an enemy). [Wine is a turncoat, first a friend, then an enemy.]
That's politics. Your friend one day is your enemy the next and vice versa.
Today’s enemy may be tomorrow’s ally (and vice versa).
My second husband believed I had such a fickle attitude to friendship that each Friday he would update the list of my 'Top Ten' friends in the manner of a Top Of The Pops chart countdown.
Men's minds are given to change in hate and friendship.
One must always be ready to change sides with justice, that fugitive from the winning camp.
I've seen a lot of people jump on and off my bandwagon.