How about a little Ancient Greek? We all know of Aesop’s fables; the great original storyteller who used his stories about nature to convey tropes we still use today. Here is one of his puns or, morals:
Ὁ φίλος ἐπεὶ ἐν τοῖς κινδύνοις τὸν φίλον λεὶπει, οὐ τᾖ ἀληθείᾳ φίλος.
The friend that when in danger forsakes a friend, [is] not a true friend at all.
El amigo que estando en peligro abandona un amigo, no es un verdadero amigo.
Amicus ubi in periculum amico relinquit, verus amicus non est.
Notice the friends are in danger together, making the ‘leaving’ that much more important. Both in Greek and Latin ‘leaving’ had a huge importance. The Ancient Greek protected the man next to him with his shield in the phalanx formation; thus if you left, you quite literally caused the death of the man next to you and the breaking of the phalanx. Further, the person next to you in formation was, more than likely, a very close friend, if not a father, uncle, or someone in your family, since the phalanx was formed by house, district, and neighborhood. Also, ‘philo’ was another word for love, love that grew out of common goals and experiences (think philadelphia – the city of ‘Brotherly Love’), so whoever you left behind to die was much more than just a buddy.
Although not tied by family, Romans thought of abandoning the line just as badly; a concept shared with the new brotherhoods of today, such as those created out of the military, aka Brothers at Arms who ‘leave no one behind.’ We could just as easily say ‘the lover (out from shared experiences) who, when in danger, leaves the beloved behind is no true lover at all.’