To clarify, these phrases regarding the Israelites' ascent can be understood as distinguishing between prohibition and permission. The divine prohibition establishes the boundaries set by God, ensuring that no one would exceed these limits when approaching Mount Sinai. This injunction was firmly upheld throughout the time God revealed Himself to the Israelites at the mountain, as underscored by the verses at the chapter's conclusion, which reinforce the restrictions on overstepping the designated boundaries.
Conversely, the permission granted to the Hebrews allowed them to approach Mount Sinai, and this permission did not specify any limitations. It was mandated that whenever the trumpets sounded, the people should come forward to the mountain to receive the law, specifically as illustrated in verse 17, indicating they could come to the very base of the mountain. Thus, it is evident that while the Israelites were permitted to ascend Mount Sinai, they were limited to specific appointed areas—not to the summit, but to designated spots that were not elevated, just at the foot of the mountain, where the ascent typically begins.
It is recognized that the terrain of tall mountains extends broadly at their base, making the initial ascent imperceptible and relatively easy. When God spoke to Moses from the summit, the people needed to ascend to some extent to hear God's voice. In summary, the Israelites were not allowed to explore every part of Mount Sinai to witness the glory of God; however, they were invited to approach certain locations to hear His words. They were forbidden to reach the top, with limits imposed on their ascent, but they could stand at the height of the mountain within the permitted boundaries.