Exodus 19:12 in the World English Bible
You shall set bounds to the people all around, saying, ‘Be careful that you don’t go up onto the mountain, or touch its border. Whoever touches the mountain shall be surely put to death.
Context
11 And be ready against the third day: for the third day the LORD will come down in the sight of all the people upon mount Sinai.
12 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:
13 There shall not an hand touch it, but he shall surely be stoned, or shot through; whether it be beast or man, it shall not live: when the trumpet soundeth long, they shall come up to the mount.