Amen & hallelujah: the oldest borrowings
From Hebrew ʾāmēn — "so be it; truly," from a root meaning firm and faithful — the word entered English before the year 1000, carried by Christian liturgy. Halləlū-yāh, "praise Yah," is a Psalm refrain (it appears 24 times in Psalms) that was carried untranslated into every Christian language, reaching English by 1525–35. Two Hebrew words so useful that no one ever dared translate them.
