12 Put limits for the people around the mountain and tell them, ‘Be careful that you do not approach the mountain or touch the foot of it. Whoever touches the mountain is to be put to death.

Read Exodus 19:12 Using Other Translations

And thou shalt set bounds unto the people round about, saying, Take heed to yourselves, that ye go not up into the mount, or touch the border of it: whosoever toucheth the mount shall be surely put to death:
And you shall set limits for the people all around, saying, 'Take care not to go up into the mountain or touch the edge of it. Whoever touches the mountain shall be put to death.
Mark off a boundary all around the mountain. Warn the people, ‘Be careful! Do not go up on the mountain or even touch its boundaries. Anyone who touches the mountain will certainly be put to death.