Deuteronomy 4:11-13

And ye came near and stood under the mountain; and the mountain burned with fire unto the midst of heaven, with darkness, clouds, and thick darkness. {midst: Heb. heart} And the LORD spake unto you out of the midst of the fire: ye heard the voice of the words, but saw no similitude; only {ye heard} a voice. {only...: Heb. save a voice} And he declared unto you his covenant, which he commanded you to perform, {even} ten commandments; and he wrote them upon two tables of stone.