The adjective ξενος (xenos) means unfamiliar, foreign or strange, hence our English word xenophobia: the fear of strangers or strangeness. It's unclear where our word comes from — and thus what it essentially, most fundamentally means — but where in English the word strange has a rather negative connotation, in Greek it has quite the opposite, and rather describes a friend we haven't met yet (this famous Irish dictum was coined by poet Edgar Guest in 1915 but is probably much older). The substantial use of our adjective ξενος (xenos) would describe a guest-friend (rather than a living next-door friend), or even a foreign nation state with whom Greece was bound by treaty of friendship and hospitality.

The ancients had figured out that any society benefits greatly from its resident foreigners — foreign ideas, art and even food stirs up the existing pot; new experiences keep the mind limber, and foreign bacteria (with foreign DNA) are crucially important in keeping the native body healthy. Obviously, any native society would succumb from too large an influx of foreigners, but without a critical minimum mass of strangeness, the native population would wither and succumb just the same.

The name Hebrew means "crosser over" and may literally have denoted a "stranger". Students of YHWH (or "followers of Logos", if you will) famously derive their ancestry from Abraham the Über-stranger (Genesis 23:4, Matthew 3:9, Galatians 3:7), and in Egypt, Israel was a stranger and waxed from a mere family to a great nation (Exodus 23:9) — hence the edict: "The stranger who resides with you shall be to you as the native among you, and you shall love him as yourself, for you were aliens in the land of Egypt; I am YHWH your God" (Leviticus 19:34, Matthew 22:37-40).

In Hebrew society, the rights (and plights) of strangers were written into the very core of the legal code: strangers were protected by law (Exodus 22:21, Leviticus 19:10); all law (save, perhaps, for certain elements of Passover; Exodus 12:43-49) applied to strangers equally as to natives (Leviticus 18:26, 24:22); the Sabbath applied to strangers (Exodus 20:10), and even God's very words (Psalm 12:6) were in crucial part delivered to the Jews through strangers: "Indeed, He will speak to this people through stammering lips and a foreign tongue" (Isaiah 28:11, Matthew 25:35, Hebrews 13:2).

Recognizing kin is an important survival mechanism and animals commonly react negatively to strangeness. Somewhere along mankind's development into modernity, natural fear of unfamiliarity appears to have morphed into an appreciation of it. We even invented a word for exposure to pleasant unfamiliarity: entertainment — which today is a sad euphemism for "keep the entitled host from being bored" but which in the olden days focused on the comfort of the guest. The word entertainment consists of the Latin elements inter (meaning among) and tenir (meaning to hold). That means that our word entertainment means "to hold among" and speaks of generous inclusion of something that doesn't naturally match. In that sense, our word entertainment is very similar to the word kindness, which likewise acknowledges a stranger as kin or alike-in-kind.

When humans began to understand natural law and became more confident in life, shouts of fear of strangeness became laughter, and this transition is marked in the generation of Abraham's son Isaac, whose name means He Will [Cause To] Laugh (also see our article on the noun γαμος, gamos, marriage).

The celebrated Greek culture would not have been possible without the alphabet, which derived from the Semitic alphabet, which was imported into the Greek language basin along with some crucial elements of the Hebrew wisdom tradition (see our articles on the names Colossae and Hellas). That suggests that Greece's signature positive attitude toward strangers was essentially as Jewish as the alphabet. One of the epithets of Zeus was ξενιος (xenios), the Hospitable, as Greek's supreme deity was also considered to be the Protector of Friendship and Hospitality. This too is a Hebrew idea, as the Psalmist had noted: "YHWH protects the strangers" (Psalm 146:9).

The plural of our word, namely ξενοι (xenoi) or Strangers, served to refer to one of the social strati of Greek society — which also included the ελευθεροι (eleutheroi), the Free (and licensed to govern); the δουλοι (douloi), the Employed (not licensed to govern); the πτωχοι (ptochoi), the Destitute (unemployed and not free); the μακαριοι (makarioi) , the Untouchables or great ones (the wealthy elite, the 1%). Someone classified among the ξενοι (xenoi) was obviously someone who wasn't classified as a slave or destitute (which would cover disenfranchised foreign refugees and prisoners of war), and thus a wealthy merchant or ambassador from a foreign court. Such Xenoi, such Strangers, were allowed all the perks and joys that befell the Eleutheroi, the Free, with the crucial exception of the right to govern or draft policy.

Our adjective ξενος (xenos) doesn't simply mean strange(r) but rather guest or "[one] shown hospitality to" (1 Peter 4:9) — there is no other word for guest; this is it. It's the opposite of all things familiar, but not necessarily negative and much rather positive (Isaiah 42:9). Hence, the men of Athens (natives and guests) were obsessed with novelty (Acts 17:21). And in 1 Peter 4:12, the author likewise, albeit somewhat enigmatically, speaks of not being surprised by an unfamiliar thing coming about. In Romans 16:23, Paul calls Gaius his ξενος (xenos), and although in very rare occasions this word may indeed denote the host (as most translations have it), it commonly denotes the guest, which means that Gaius was the guest of Paul and of the whole Assembly. This in turn appears to play with the idea that although the fathers of the older generations received the younger as their children, the younger generations, who will receive the New Jerusalem in their midst, will host the fathers of the older generations as brothers and guests in the resurrection.

Our word in Hebrews 13:9 may denote foreign teachings, but also the much broader effects of the mere presence of foreign people (and their things, animals, foods, music, stories, customs, and so on). Likewise, Acts 17:18 speaks of "foreign daimonions", or happenings that were neither expected nor explicable by the common canon of received wisdom.

Our adjective is used 14 times in the New Testament, see full concordance, and from it derive: