Exodus 24:16-18

Young's Literal Translation

¹⁶ and the honour of Jehovah doth tabernacle on mount Sinai, and the cloud covereth it six days, and He calleth unto Moses on the seventh day from the midst of the cloud.

¹⁷ And the appearance of the honour of Jehovah [is] as a consuming fire on the top of the mount, before the eyes of the sons of Israel;

¹⁸ and Moses goeth into the midst of the cloud, and goeth up unto the mount, and Moses is on the mount forty days and forty nights.