TgO Ex31:18 :תְרֵין לוּחֵי סָהְדוּתָא לוּחֵי אַבנָא כְתִיבִין בְאַצבְעָא דַיוי‏ : the two tablets of testimony: stone tablets written by the finger of the Lord
See the entire entry for ktb vb. to write