By “Seir” is to be understood the mountain-land of the Edomites, and by “mount Paran” the range which forms the northern boundary of the desert of Sinai (compare Genesis 14:6 note). Thus the verse forms a poetical description of the vast arena upon which the glorious manifestation of the Lord in the giving of the covenant took place.
With ten thousands of saints - Render, from amidst ten thousands of holy ones: literally from myriads of holiness, i. e., holy Angels (compare Zechariah 14:5). God is represented as leaving heaven where He dwells amidst the host of the Angels 1 Kings 22:19 and descending in majesty to earth Micah 1:3.
A fiery law - more literally as in the margin, with perhaps an allusion to the pillar of fire Exodus 13:21. The word is much disputed.