A thought -provoking quote indeed, Positive Change.
Yes, if only, we all realize that in the cyclic existence that is Samsara, we can be friends in one lifetime and enemies in another. There is an interesting story(which has a similar 'message') in Liberation in the Palm of your Hand. A sage and realized master chuckled to himself as he passed a domestic scene.
'A man was bouncing his baby boy on his lap, who had been the enemy he had killed because that guy had raped his wife. The wife begot him a son who was this enemy. At the same time, this man was eating a fish, who actually was his father, who had been a fisherman in that area before he died. Also, at the same time, he was kicking away the 'family' dog, who was trying to grab the fish-bones from him. The dog was the incarnation of his mother, who had passed away too'.
The sage chuckled at this vision and, as he went on his way, he said to himself:"Samsara is such a farce".
If only we do not divide people into categories, labelling one category as 'friends' , another category as 'enemies' and yet another category as 'strangers'. If only, we can view all, with equanimity, as beings who , like us, want to have happiness and don't want to experience suffering, then there will be no conflict or war.
Better still, if only we can see all beings as having been our mothers before, and seek to remember and repay their kindnesses to us, how much love and kindness and peace and compassion there will be among all beings.