Explanatory Notes on the Whole Bible, by John Wesley, [1754-65], at sacred-texts.com
psa 114:2Judah - Or Israel, one tribe being put for all. Judah he mentions as the chief of all the tribes.
psa 114:4The mountains - Horeb and Sinai, two tops of one mountain, and other neighbouring mountains.
psa 114:7Tremble - The mountains did more than what was fit at the appearance of the great God.