in the twinkling of an eye

The story

1. Middle English · inherited fromin the twynklyng of an iȝe
2. English todayin the twinkling of an eye

From Middle English in the twynklyng of an iȝe, in þe twynklynk of an eiȝe, from the Bible, 1 Corinthians 15:52: We shall all be changed, in a moment, in the twinkling of an eye, at the last trumpet.