Building on the answer of @FrankHubeny, there is one very important point to be made:
In the original, there are words "h i g h l i g h t e d" with spaces. Thus, the correct and full translation of the aphorism reads (with emphases):
Inimitable. — There is an enormous suspense and span between envy and friendship, between self-contempt and pride: the Greek lived in the former, the Christian in the latter.
Mind that I rather use "suspense" for "Spannung" since it can mean "strain", but only in mechanical contexts. The slightly more equivocal translation would be the plain "tension" and this probably transports the ambiguity of the original best but I wanted to induce a counter-intuition to the original translation here. And I use "span" for "Spannweite" since for a native speaker it intuitively hints at the variance and variety indicated. Also, "Spannung" and "Spannweite" are obviously used for rhetorical means, i.e. as a wordplay, and should not necessarily be translated literally, i.e. in mechanical and spatial terms, here.
Thus, Nietzsche indicates that the Greek lived between the extremes of envy and friendship, while the Christians lived between the extremes of self-contempt and pride, as their cultural cornerstones: Friendship and self-contempt* are the corresponding cultural/ethical ideals while envy and pride are their opposites, i.e. the corresponding paths to evil. If you look at ethical writings from both traditions, his observation has some merit.
Additionally, he points out that the span in between these extremes is wide and diverse enough to accommodate a complete cultural spectrum in both cases, i.e. they should not be considered as either-or. This is a pretty Aristotelean point he is making here: The world is not black and white and life happens in shades of grey (pun intended), i.e. between "ideal" good and "ideal" evil.
*Please let us not delve into discussions about how self-contempt can never be the Christian ideal. Nietzsche was not fond of Christian dogma and it indeed is well in-character for him to say such things.