My root was spread out by the waters - Margin, as the Hebrew, “opened.” The meaning is, that it was spread abroad or extended far, so that the moisture of the earth had free access to it; or it was like a tree planted near a stream, whose root ran down to the water. This is an image designed to denote great prosperity. In the East, such an image would be more striking than with us. Here green, large, and beautiful trees are so common as to excite little or no attention. In such a country as Arabia, however, where general desolation exists, such a tree would be a most beautiful object, and a most striking image of prosperity; compare DeWette on Psalms 1:3.
And the dew lay all night upon my branch - In the absence of rain - which seldom falls in deserts - the scanty vegetation is dependent on the dews that fall at night. Those dews are often very abundant. Volney (Travels i. 51) says, “We, who are inhabitants of humid regions, cannot well understand how a country can be productive without rain, but in Egypt, the dew which falls copiously in the night, supplies the place of rain.” See, also, Shaw’s Travels, p. 379. “To the same cause also (the violent heat of the day), succeeded afterward by the coldness of the night, we may attribute the plentiful dews, and those thick, offensive mists, one or other of which we had every night too sensible a proof of. The dews, particularly, (as we had the heavens only for our covering), would frequently wet us to the skin.” The sense here is, as a tree standing on the verge of a river, and watered each night by copious dews, appears beautiful and flourishing, so was my condition. The Septuagint, however, renders this, “And the dew abode at night on my harvest” - καί δρόσος ἀυλισθήσεται ἐν τῷ θερισμῷ μου kai drosos aulisthēsetai en tō therismō mou. So the Chaldee - וטלא בחצדי יבית. A thought, similar to the one in this passage, occurs in a Chinese Ode, translated by Sir William Jones, in his works, vol. ii. p. 351:
Vide illius aquae rivum
Virides arundines jucunde luxuriant!
Sic est decorus virtutibus princeps noster!
“Seest thou yon stream, around whose banks
The green reeds crowd in joyous ranks?
In nutrient virtue and in grace,
Such is the Prince that rules our race.”
Dr. Good