Archaic KJV Word
Quick And Dead
Modern equivalent: the living and the dead
What Was Lost
The total scope of judgment. The quick (the living) and the dead -- everyone who has ever existed or ever will exist stands before this Judge. The phrase was a creedal formula (it appears in the Apostles' Creed) that compressed universal judgment into five monosyllables. 'The living and the dead' is accurate but lacks the creedal weight.
Closest Survivor in Modern English
quickened (still faintly carries the 'made alive' meaning in theological contexts)
Peak Usage (1611)
KJV Acts 10:42 -- 'Ordained of God to be the Judge of quick and dead'; 2 Timothy 4:1 -- 'Who shall judge the quick and the dead'
Died ~1850
Quick narrowed to 'fast,' making 'the quick and the dead' sound like a comment about speed rather than the comprehensive scope of divine judgment over all who live and all who have died.
What Replaced It
“the living and the dead”
Accurate but flat; 'the quick and the dead' had a poetic gravity that paired two monosyllables in perfect balance