Moses entered the cloud as he went up on the mountain, and he remained on the mountain forty days and forty nights.
The public ceremony of sealing the covenant being over, Moses is called up to receive further instructions, which we have in the following chapters. I. He is called up into the mount, and there he remains six days at some distance.
Commenting on Exodus 24:12-18
Moses went into the midst of the cloud--the visible token of God's presence. Divine grace animated and supported him to enter with holy boldness. Moses was in the mount forty days and forty nights--The six days spent in waiting are not included. During that protracted period he was miraculously supported (Deu 9:9), on a peak scarcely thirty paces in compass. Next: Exodus Chapter 25
Forty days and forty nights - During the whole of this time he neither ate bread nor drank water; see Exo 34:28; Deu 9:9. Both his body and soul were so sustained by the invigorating presence of God, that he needed no earthly support, and this may be the simple reason why he took none.