Charles H. Spurgeon on Psalms 133:3

As the dew of Hermon, etc. As touching this similitude, I think the prophet useth the common manner of speaking. For whereas the mountains oftentimes seem to those that behold them afar off, to reach up even unto heaven, the dew which cometh from heaven seemeth to fall from the high mountains unto the hills which are under them. Therefore he saith that the dew descendeth from Hermon unto the mount Sion, because it so seemeth unto those that do behold it afar off. —Martin Luther.