Or, His eyes are doves. The comparison is to doves seen by streams of water washing in milk (i. e., milk-white), and sitting on fulness (i. e., on the full or abundant water-flood).
Fitly set - This rendering supposes that the eyes within their sockets are compared to precious stones set in the foil of a ring (see the margin); but the other rendering is preferable. The milk-white doves themselves, sitting by full streams of water, or reflected in their flittings athwart the glassy surface, present images of the calm repose and vivid glances of the full pure lustrous eyes of the beloved.

His eyes are as the eyes of doves - See on Song 4:1 (note).
Washed with milk - The white of the eye, exceedingly white. By the use of stibium, in the East, the eye is rendered very beautiful; and receives such a lustre from the use of this article, that, to borrow the expression of a late traveler, "their eyes appear to be swimming in bliss." I believe this expression to be the meaning of the text.
Fitly set - Or, as the margin, very properly, sitting in fullness; not sunk, not contracted.

His eyes are as the eyes of doves,.... the church's eyes are said to be, Song 1:15; which are her ministers, endowed with dove like gifts in measure, as Christ is without measure, in fulness; but these are Christ's eyes, which may signify his omniscience, who has seven eyes, Zac 3:9; especially as that has respect unto and is concerned with his people in a way of grace and mercy, and so must look very beautiful in their view: his eyes are like "doves' eyes"; not fierce and furious, but loving and lovely; looking upon his people, under all their trials and afflictions, with sympathy and concern, to deliver them out of them: and like the eyes of doves
by rivers of waters: Sanctius thinks the allusion is to the humours in which the eye is enclosed, and, as it were, swims in; hence the eyes are called "natantia lumina", by Virgil (h); but it denotes eyes like those of doves, quick and lively, as clean as milk white doves, as if they had been "washed in milk"; clear and perspicuous, sharp sighted, and behold all persons and things, in all places, and at once; and as doves look only to their mates, so Christ's eyes of love are only on his church; he looks to none but her with his eye of special and peculiar love. Moreover, his eyes are like the eyes of doves "by the rivers of waters"; which denotes the fixedness and constancy of them: doves, by the river side, keep their eyes fixed on the purling streams, and in drinking, as Pliny (i) observes, do not erect their necks, and lift up their heads, but, keeping their eyes upon the water, drink a large draught, in the manner the beasts do; and they delight in clean water, of which they drink, and with which they wash (k): Christ, being greatly delighted with his people, has fixed his eyes on them, and he never withdraws them from them; for these waters may point at the object of Christ's love, even Gospel churches, consisting of such as are justified and sanctified by his grace, compared to "clean water"; among whom the doctrines of the Gospel are powerfully preached, the ordinances purely administered, the waters of the sanctuary flow, by which souls are delighted and refreshed; and to these Christ looks, Isaiah 66:2; and his eyes being like doves' eyes,
washed with milk, may denote the purity of them, being purer eyes than to behold iniquity; and the meekness and mildness of them, not red and wrathful, but full of mercy, pity, and compassion, as if they had been washed with milk. And they are said to be,
fitly set; or "sitting in fulness" (l); such as exactly fill up their holes; are set neither too, high nor too low; neither sunk in too much, nor stand out too far; but are like precious stones, in an enclosure of gold or silver, to which the allusion is; as diamonds set in a ring; or as the precious stones in the high priest's breast plate, which exactly filled the cavities made for them, and hence are called "stones of fulness", Exodus 25:7; or, "set by fulness" (m); that is, by full channels of water, where doves delight to be; and may denote the fulness of grace, and the flows of it, by which Christ sits and dwells, and leads his people to, Revelation 7:17; or, "setting upon fulness" (n); on the world, and the fulness of it, which is his, and he gives as much of it to his people as he think fit; and on the vast numbers of persons and things in it, and the vast variety of actions done therein; which shows the extensiveness of his omniscience: and on the "fulness" of time, fixed by him and his Father, for his coming into the world, to do the great work of redemption in it; and which, before it came, he was looking, waiting, and watching, and as it were longing till it came: and on his "fulness", the church, which is the fulness of him that filleth all in all, until he has gathered them all in, and filled them with all the gifts and graces of the Spirit, designed for them: and on the "fulness" of the Gentiles, until they are all brought in: and on his own "fulness"; both personal, "the fulness of the Godhead", which he had his eyes upon, when he undertook the work of redemption, and which supported him in it, and carried him through it; and upon his dispensatory "fulness", or fulness of grace, as Mediator, to supply the wants of his people, under all their straits and difficulties, temptations and afflictions: all which must make him exceeding lovely in the eyes of his people.
(h) Aeneid. l. 5. So Ovid. Fast. l. 6. "animique oculique natabant". (i) Nat. Hist. l. 10. c. 34. (k) Varro de Rustic. c. 3. s. 7. (l) "siti insitione", Junius & Tremellius, Piscator. (m) "Ad plenitudinem", Tigurine version, Bochart; "juxta plenitudinem", Vatablus; so some in Brightman; "juxta fluenta plenissima" V. L. Septuagint, Syriac, and Arabic versions. (n) "Super plenitudinem", Montanus, Mercerus.

as the eyes of doves--rather, "as doves" (Psalm 68:13); bathing in "the rivers"; so combining in their "silver" feathers the whiteness of milk with the sparkling brightness of the water trickling over them (Matthew 3:16). The "milk" may allude to the white around the pupil of the eye. The "waters" refer to the eye as the fountain of tears of sympathy (Ezekiel 16:5-6; Luke 19:41). Vivacity, purity, and love, are the three features typified.
fitly set--as a gem in a ring; as the precious stones in the high priest's breastplate. Rather, translate as Vulgate (the doves), sitting at the fulness of the stream; by the full stream; or, as MAURER (the eyes) set in fulness, not sunk in their sockets (Revelation 5:6), ("seven," expressing full perfection), (Zac 3:9; Zac 4:10).

12 His eyes like doves by the water-brooks,
Bathing in milk, stones beautifully set
The eyes in their glancing moistness (cf. ὑγρότης τῶν ὀμμάτων, in Plutarch, of a languishing look), and in the movement of their pupils, are like doves which sip at the water-brooks, and move to and fro beside them. אפיק, from אפק, continere, is a watercourse, and then also the water itself flowing in it (vid., under Psalm 18:16), as (Arab.) wadin, a valley, and then the river flowing in the valley, bahr, the sea-basin (properly the cleft), and then also the sea itself. The pred. "bathing" refers to the eyes (cf. Song 4:9), not to the doves, if this figure is continued. The pupils of the eyes, thus compared with doves, seem as if bathing in milk, in that they swim, as it were, in the white in the eye. But it is a question whether the figure of the doves is continued also in ישׁבות על־מלּאת. It would be the case of milleth meant "fulness of water," as it is understood, after the example of the lxx, also by Aquila (ἐκχύσεις). Jerome (fluenta plenissima), and the Arab. (piscinas aqua refertas); among the moderns, by Dpke, Gesen., Hengst., and others. But this pred. would then bring nothing new to Song 5:12; and although in the Syr. derivatives from melā' signify flood and high waters, yet the form milleth does not seem, especially without מים, to be capable of bearing this signification. Luther's translation also, although in substance correct: und stehen in der flle (and stand in fulness) (milleth, like שׁלמותא of the Syr., πληρώσεως of the Gr. Venet., still defended by Hitz.), yet does not bring out the full force of milleth, which, after the analogy of כּסּא, רצפה, appears to have a concrete signification which is seen from a comparison of Exodus 25:7; Exodus 27:17, Exodus 27:20; Exodus 39:13. There מלּאה and מלּאים signify not the border with precious stones, but, as rightly maintained by Keil, against Knobel, their filling in, i.e., their bordering, setting. Accordingly, milleth will be a synon. technical expression: the description, passing from the figure of the dove, says further of the eyes, that they are firm on (in) their setting; על is suitable, for the precious stone is laid within the casket in which it is contained. Hitzig has, on the contrary, objected that מלאת and מלאים denote filling up, and thus that milleth cannot be a filling up, and still less the place thereof. But as in the Talm. מוּליתא signifies not only fulness, but also stuffed fowls or pies, and as πλήρωμα in its manifold aspects is used not only of that with which anything is filled, but also of that which is filled (e.g., of a ship that is manned, and Ephesians 1:23 of the church in which Christ, as in His body, is immanent), - thus also milleth, like the German "Fassung," may be used of a ring-casket (funda or pala) in which the precious stone is put. That the eyes are like a precious stone in its casket, does not merely signify that they fill the sockets, - for the bulbus of the eye in every one fills the orbita, - but that they are not sunk like the eyes of one who is sick, which fall back on their supporting edges in the orbita, and that they appear full and large as they press forward from wide and open eyelids. The cheeks are next described.

Of doves - Lovely and pleasant, chaste and innocent. Rivers - Where they delight to abide. Milk - Doves of a milk white colour.