Exodus 24:12

The Lord said unto Moses, Come up There were different stations on the mountain. The glory of the Lord occupied the highest place, the top of the mountain: to this place Moses is now called up, leaving the elders below to wait for him, and commissioning Aaron and Hur to transact any business in his absence. It has been thought that Moses might not expect so long a continuance in the mount with God as forty days and forty nights, when he enjoined the elders to tarry for him on the mount, and commissioned Aaron and Hur to go backward and forward between them and the people; and that it is not probable the elders continued all that time upon that part of the mountain where he left them. Concerning this, however, nothing can be affirmed with certainty.