The Targum Pseudo-Jonathan intensifies the penalty for trespass at Sinai: "Touch it not with the hand; for he will be stoned with hailstone, or be pierced with arrows of fire; whether beast or man, he will not live. But when the voice of the trumpet is heard, they may go up (forwards) towards the mount" (Exodus 19:13).
The Aramaic is vivid where the Hebrew is plain. The Hebrew says simply stoned or shot. The Aramaic identifies the weapons: hailstone and arrows of fire. These are not human weapons. They are the weapons of heaven itself — the same hailstones from the plague in Egypt (Exodus 9:24), the same fire that consumed Nadab and Abihu at Leviticus 10:2.
The mountain would defend itself. No human executioner would need to be appointed. The holiness at the boundary would take its own payment.
And then the dramatic opening: "when the voice of the trumpet is heard, they may go up." The shofar would sound, and the prohibition would invert. The same boundary that killed the trespasser would, at the signal, open the approach. Sacred space is not eternally closed. It is closed on a schedule.
The takeaway: the holy is not hostile to us; it is patient with us, and it opens when it is ready. Our job is not to force the opening but to wait for the signal and walk up when the trumpet sounds.