They go up by the mountains, they go down by the valleys,.... The Targum is,"they ascend out of the deep to the mountains;''that is, the waters, when they went off the earth at the divine orders, steered their course up the mountains, and then went down by the valleys to the place appointed for them; they went over hills and dales, nothing could stop them or retard their course till they came to their proper place; which is another instance of the almighty power of the Son of God.
Some render the words, "the mountains ascended, the valleys descended "; and then the meaning is, when the depth of waters were called off the earth, the mountains and valleys appeared, the one seemed to rise up and the other to go down; but the former reading seems best, and emblematically describes the state of God's people in this world, in their passage to their appointed place; who have sometimes mountains of difficulties to go over, and which seem insuperable, and yet they surmount them; sometimes they are upon the mount of heaven by contemplation, and have their hearts and affections above; they mount up with wings as eagles; sometimes they are upon the mount of communion with God, and by his favour their mount stands strong, and they think they shall never be moved; at other times they are down in the valleys, in a low estate and condition; in low frames of soul, in a low exercise of grace, and in the valley of the shadow of death, of afflictive providences in soul or body: and as the waters, thus steering their course under a divine direction, and by an almighty power, at length came unto the place which, the psalmist says, thou hast founded for them, meaning the seas; which the Lord founded and prepared for the reception of them; and which collection of waters in one place he called by that name, Ge 1:10.
So the Lord's people, through a variety of circumstances, trials, and exercises, will be all brought safe to the place appointed for them, and prepared by Christ in his Father's house; where they will be swallowed up in the boundless ocean of everlasting love.