He shall descend as the rain upon the mown grass. This comparison may seem at first sight to be somewhat harsh; but it elegantly and appositely expresses the great advantage which is derived by all from the good and equitable constitution of a kingdom. Meadows, we know, are cut in the beginning of summer when the heat prevails; and did not the earth imbibe new moisture by the falling rain, even the very roots of the herbage would wither by reason of the barren and parched state of the soil. David, therefore, teaches us that as God defends the earth from the heat of the sun by watering it, so he in like manner provides for the welfare of his Church, and defends it under the government of the king. But this prediction has received its highest fulfillment in Christ, who, by distilling upon the Church his secret grace, renders her fruitful.

He shall come down - That is, The influence of his reign will be like fertilising showers. The word" he" in this place might have been "it," referring to his reign, or to the influence of his government.
Like rain upon the mown grass - The word rendered "mown grass" - גז gêz - means properly "a shearing," and is applied in Deuteronomy 18:4, and Job 31:20, to a fleece of wool. So it is understood here by the Septuagint, by the Latin Vulgate, by the Syriac, and by Luther; and, in accordance with this, it has been supposed by some that there is an allusion to the dew that descended on the fleece spread out by Gideon, Judges 6:37. The Chaldee Paraphrase renders it, "As the grass that has been eaten off by locusts;" where the idea would be that after locusts have passed over a field, devouring everything, when the rain descends the fields revive, and nature again puts on the appearance of life. This idea is adopted by Rosenmuller. The common interpretation, however, which refers the word to a "mowing," that is, a "mown meadow," is probably the correct one; and thus understood, the image is very beautiful. The reign of the Messiah would resemble the gently descending shower, under which the grass which has been mown springs up again with freshness and beauty.
As showers that water the earth - literally, "like showers, the watering of the earth." The original word rendered "that water" suggests the idea of distilling, or "gently" flowing.

He shall come down like rain upon the mown grass - The word גז gez, which we translate mown grass, more properly means pastured grass or pastured land; for the dew of the night is intended to restore the grass which has been eaten in the course of the day. This very idea the Chaldee has seized, and renders the place thus: "He shall descend gently, like rain upon the grass which has been eaten by the locust." But there seems to be a reference to the thick night dews which in summer fall on the pasturages, and become the means of restoring the grass consumed in the day-time by the cattle. This is finely expressed by the most accomplished of all poets and agriculturists: -
Et quantum longis carpent armenta diebus,
Exigua tantum gelidus ros nocte reponet.
Virg. Geor. ii., ver. 201.
"For what the day devours, the nightly dew
Shall to the morn by pearly drops renew."
Dryden.
Or to leave poetry, which always says too much or too little, the plain prose is: -
"And as much as the flocks crop in the long days,
So much shall the cold dew restore in one short night."
As showers that water the earth - The influence of the doctrine and Spirit of Christ on the soul of man shall be as grateful, as refreshing, and as fructifying, as the nightly dews on the cropped fields, and the vernal showers on the cultivated lands. Without his influence all tillage is vain; without him there can neither be seed nor fruit.

He shall come (g) down like rain upon the mown grass: as showers [that] water the earth.
(g) As this is true in all godly kings, so it is chiefly verified in Christ, who with his heavenly dew, makes his Church ever to flourish.

He shall come down like rain upon the mown grass,.... That is, the King and King's Son, the Messiah, whose coming is compared to rain, and showers of it; see Hosea 6:3; and may be understood of his incarnation; when, like rain, he came down from heaven; not by an illapse or entrance of the human nature, which before was not in him; nor by local motion of his divine Person, with which that will not agree; but by assumption of human nature into union with him, as the Son of God; which was an instance of his condescending grace: like rain, he had no father as man; see Job 38:28; but was born of a virgin, through the power of the Holy Ghost; which was very marvellous, like the dew that fell on Gideon's fleece, when the earth about it was dry; which some think is here referred to. The word used signifies also a shorn fleece of wool; and so it is rendered by the Septuagint, and those versions which follow that: or, "shorn grass", shorn by locusts, as the Targum; rather by sheep, who, as by classical writers (s), are said to sheer the grass by biting it. Or, "like rain upon the fleece" (t); and as the rain is the gift of God to persons undeserving, in consequence of a decree, Job 28:26; sometimes comes suddenly, and is very grateful and refreshing; so Christ is the free gift of God to sinners, and by a decree of his; and his coming was suddenly, into his temple, and was welcome to them that looked for him; as he still is to all sensible sinners. Or this may be interpreted of the coming of Christ into the hearts of his people, by the communications of his Spirit and grace, which, like rain, came down from heaven; are dependent on the will of God, are free grace gifts, and given in abundance; and, like rain, refresh, revive, and make fruitful. Or else this may be applied to the administration of Christ's offices; as his prophetic office, his Gospel and doctrine, being from heaven, like rain, and falling, by divine direction, sometimes in one place, and sometimes in another; and like it in its effects, softening, quickening, and fructifying; and more especially it may respect the administration of his kingly office, since he is in the context spoken of as a King and Judge, and that in the latter day; whose administrations, though just and righteous; yet not cruel and severe, but mild and gentle; his commands are not grievous, nor his yoke heavy; though he will rule the wicked with a rod of iron, he holds forth the sceptre of grace and mercy to his own people; and when his kingdom shall come in all its glory, it will be times refreshing from the presence of the Lord; and his favour will be as the cloud of the latter rain; see Acts 3:19;
as showers that water the earth: signifying the same. The word is only in this place, and is used in the Talmud (u), in the plural number, for drops of water; and this sense of showers dropping on the earth is given by the Targum. Kimchi derives it from which, in the Syriac language, signifies to "cut"; and thinks the phrase is the same with the former, "as showers on the cut grass of the earth" (w). But perhaps the word rather designs the fissures and cracks of the earth through drought; and the sense is, that Christ's coming is like showers of rain upon the dry and parched ground, which are very acceptable to it.
(s) "Tondentes gramen oves", Ovid. de Remed. Amor. l. 1. "Tondentes gramina lanigerae pecudes", Lucret. c. 2. (t) "super vellus", V. L. Pagninus, Montanus. (u) T. Bab. Yoma, fol. 87. 1. (w) In Sepher Shorash. rad.

A beautiful figure expresses the grateful nature of His influence;

He shall come - Christ did come down from heaven, and brought or sent down from heaven his doctrine, (which is often compared to rain) and the sweet and powerful influences of his spirit.