Koh (H3541) is a deictic adverb meaning 'thus,' 'so,' 'in this way,' or 'like this.' Its most famous use is in the prophetic formula koh amar YHWH — 'Thus says the LORD' — which appears over 400 times in the Hebrew prophets. This formula introduced divine oracles and carried enormous authority: it was not the prophet's opinion but a direct quotation from the sovereign God. Koh can also mean 'here' in certain spatial contexts.
'Thus says the LORD' (koh amar YHWH) is one of the most theologically loaded phrases in the Old Testament. It is the messenger formula — the language of a royal herald announcing the king's edict. When Elijah, Isaiah, Jeremiah, or Amos prefaced their words with koh amar YHWH, they were claiming not personal authority but total divine authority. Their words were God's words.
This formula underpins the doctrine of prophetic inspiration. The New Testament's claim that 'all Scripture is God-breathed' (2 Timothy 3:16) has its roots in this Hebrew convention: the prophets genuinely believed they were transmitting the words of the living God. The formula also carries a covenantal warning dimension — when the prophets pronounced judgment 'thus says the LORD,' they were invoking the curse sanctions of the Mosaic covenant.