state, give instructions
誥 centers on formal verbal communication: stating something authoritatively or giving instructions. The two given meanings are closely related as official or deliberate speech acts.
誥 combines 言 (speech) with 告 (announce, inform), suggesting a formal or authoritative statement. The exact historical development is uncertain, but the component relationship is straightforward.
Words (言) that announce (告) something officially: imagine a herald standing before a crowd, speaking a formal proclamation. That is 誥 — to state or give instructions.
For コウ, picture a court official giving instructions in a loud, clear voice: "KOU!" The sharp sound cues コウ while the official states the decree.