Archaic KJV Word
Intercede
Modern equivalent: pray for someone
What Was Lost
The gap-standing. When Christ 'ever liveth to make intercession,' He is not merely praying from a distance but perpetually standing between God and humanity -- His own body the bridge, His own wounds the evidence, His own presence the guarantee. The Spirit's intercession is 'groanings which cannot be uttered' -- not polite prayer but anguished, wordless standing-in-the-gap.
Closest Survivor in Modern English
intercede (still used but heard as 'pray for someone' rather than 'stand in the gap between them and God')
Peak Usage (1611)
KJV Romans 8:26 -- 'The Spirit itself maketh intercession for us'; Hebrews 7:25 -- 'He ever liveth to make intercession for them'
Died still used but formalized (~1900)
Greek entynchano ('to meet with/encounter/approach on behalf of another/stand in the gap between two parties') formalized into 'pray for someone' -- losing the physical, gap-standing, between-two-parties dimension.
What Replaced It
“pray for”
Request-making; intercession was physically standing between God and the one in need -- occupying the gap
“speak on behalf of”
Verbal representation; intercession was an ongoing, bodily, present-tense standing between parties
“advocate for”
Legal; intercession was intimate and costly -- the intercessor bore the weight of both parties