God hath spoken in his holiness; I will rejoice, I will divide Shechem, and mete out the valley of Succoth.
God hath spoken in his holiness - alluding to God's promise that His people should possess Canaan (Genesis 49:1-33; Deuteronomy 33:1), and vanquish their foes (Numbers 24:17-19). So the title, 'the lily of the testimony' (Shushan-eduth), refers to God's lovely promises to Israel in the law. "In His holiness" means 'in His character as the Holy One,' infinitely raised above deceit or change (Psalms 89:35; Numbers 23:19).
I will rejoice - at His sure promises. The people personified speaks: so in Psalms 60:10; Psalms 60:12, the plural follows: us
... our.
I will divide Shechem, and mete out the valley of Succoth - i:e., the whole of Canaan, alike the region east of Jordan, represented by Succoth, as also that west of Jordan, represented by Sechem, is my inalienable possession according to God's assignation. Therefore the Edomite invaders cannot oust me from it. Jacob's successive settlement at Succoth and Shechem, on his return from the same Mesopotamia whence the Israelite host was now returned, typified this occupancy of the whole land by his posterity (Genesis 33:17-18). On the reference to the division of the land in the word "I will divide," cf. Joshua 13:7; Joshua 18:8.