"Все испытывайте, хорошего держитесь"

Происхождение английского слова "святой" (holy) берет свое начало от слова "целый, неповрежденный" и это, наверное, имеет большую связь с напутствием "спаси тебя Господь"

holy
Origin: Old English hālig, of Germanic origin; related to Dutch and German heilig, also to whole

holy ['həulɪ] / 1) (обычно Holy) священный, святой; святейший Holy Father — Святейший отец (папа римский) - Holy Writ (Священное Писание, Библия) - holy water - Holy Ghost - Holy Spirit - Holy Week Syn: sacred 2) благочестивый, праведный - holy man

holy day - религиозный праздник holy day noun a day on which a religious observance is held

Некоторые словосочетания со словом holy не имеют отношения к святости и могут ввести в заблуждение:
- ёрнические версии
Holy snakes! Боже мой! Боже правый! Не может быть! Вот те на! Ну и ну!
Holy smoke! Боже мой! Боже правый! Не может быть! Вот те на! Ну и ну!
holy (adj.);
- растение расторопша по-английски : holy thistle 1) расторопша (Silybum) 2) milk thistle ;
- holystone ['həulɪstəun] - это 1. мягкий песчаник; пемза 2. чистить песчаником, пемзой

Этимология слова:
Old English halig "holy, consecrated, sacred; godly; ecclesiastical," from Proto-Germanic *hailaga- (source also of Old Norse heilagr, Danish hellig, Old Frisian helich "holy," Old Saxon helag, Middle Dutch helich, Old High German heilag, German heilig, Gothic hailags "holy"), from PIE *kailo- "whole, uninjured" (see health). Adopted at conversion for Latin sanctus.

Primary (pre-Christian) meaning is not possible to determine, but probably it was "that must be preserved whole or intact, that cannot be transgressed or violated," and connected with Old English hal (see health) and Old High German heil "health, happiness, good luck" (source of the German salutation Heil). Holy water was in Old English.

Holy has been used as an intensifying word from 1837; in expletives since 1880s (such as holy smoke, 1883, holy mackerel, 1876, holy cow, 1914, holy moly etc.), most of them euphemisms for holy Christ or holy Moses. Holy Ghost was in Old English (in Middle English often written as one word). Holy League is used of various European alliances; the Holy Alliance was that formed personally by the sovereigns of Russia, Austria, and Prussia in 1815; it ended in 1830.

P.S. Заголовок появился благодаря словам апостола Павла о пророчестве:

https://ru.wikipedia.org/wiki/Пророк