And when she could not longer hide him, she took for him an ark of bulrushes, and daubed it with slime and with pitch, and put the child therein; and she laid it in the flags by the river's brink.

And when she could hide him no longer, she took a basket made of bulrushes, and daubed it with slime and pitch: and put the little babe therein, and laid him in the sedges by the river's brink,

And when she could no longer hide him, she took for him an ark of reeds, and plastered it with resin and with pitch, and put the child in it, and laid it in the sedge on the bank of the river.

and she hath not been able any more to hide him, and she taketh for him an ark of rushes, and daubeth it with bitumen and with pitch, and putteth the lad in it, and putteth it in the weeds by the edge of the River;

And when she was no longer able to keep him secret, she made him a basket out of the stems of water-plants, pasting sticky earth over it to keep the water out; and placing the baby in it she put it among the plants by the edge of the Nile.

And when she was no longer able to hide him, she took a small basket woven of bulrushes, and she smeared it with pitch as well as tar. And she placed the little infant inside, and she laid him in the sedges by the bank of the river.

Et quia illum abscondere amplius non poterat, accepit ei arcam arundineam, et oblevit eam bitumine et pice, et reposuit in ca infantulum: exposuitque in carecto, juxta ripam fluminis.

The ark was made of the papyrus which was commonly used by the Egyptians for light and swift boats. The species is no longer found in the Nile below Nubia. It is a strong rush, like the bamboo, about the thickness of a finger, three cornered, and attains the height of 10 to 15 feet. It is represented with great accuracy on the most ancient monuments of Egypt.
Slime and pitch - The "slime" is probably the mud, of which bricks were usually made in Egypt, and which in this case was used to bind the stalks of the papyrus into a compact mass, and perhaps also to make the surface smooth for the infant. The pitch or bitumen, commonly used in Egypt, made the small vessel water-tight.
In the flags - This is another species of the papyrus, called tuff, or sufi (an exact equivalent of the Hebrew סוּף sûph), which was less in size and height than the rush of which the ark was made.

An ark of bulrushes - תבת גמא tebath gome, a small boat or basket made of the Egyptian reed called papyrus, so famous in all antiquity. This plant grows on the banks of the Nile, and in marshy grounds; the stalk rises to the height of six or seven cubits above the water, is triangular, and terminates in a crown of small filaments resembling hair, which the ancients used to compare to a thyrsus. This reed was of the greatest use to the inhabitants of Egypt, the pith contained in the stalk serving them for food, and the woody part to build vessels with; which vessels frequently appear on engraved stones and other monuments of Egyptian antiquity. For this purpose they made it up like rushes into bundles, and by tying them together gave their vessels the necessary figure and solidity. "The vessels of bulrushes or papyrus," says Dr. Shaw, "were no other than large fabrics of the same kind with that of Moses, Exodus 2:3, which from the late introduction of planks and stronger materials are now laid aside." Thus Pliny, lib. vi., cap. 16, takes notice of the naves papyraceas armamentaque Nili, "ships made of papyrus and the equipments of the Nile:" and lib. xiii., cap. 11, he observes, Exodus ipsa quidem papyro navigia texunt: "Of the papyrus itself they construct sailing vessels." Herodotus and Diodorus have recorded the same fact; and among the poets, Lucan, lib. iv., ver. 136: Conseritur bibula Memphitis cymba papyro, "The Memphian or Egyptian boat is constructed from the soaking papyrus." The epithet bibula is particularly remarkable, as corresponding with great exactness to the nature of the plant, and to its Hebrew name גמא gome, which signifies to soak, to drink up. See Parkhurst sub voce.
She laid it in the flags - Not willing to trust it in the stream for fear of a disaster; and probably choosing the place to which the Egyptian princess was accustomed to come for the purpose specified in the note on the following verse.

And when she could not longer hide him, she took for him an ark of bulrushes, and daubed it with slime and with pitch, and (b) put the child therein; and she laid [it] in the flags by the river's brink.
(b) Committing him to the providence of God, whom she could not keep from the rage of the tyrant.

And when she could no longer hide him,.... Because of her neighbours, who might hear the crying of the child, or because of the diligent search made by Pharaoh's officers, which some think was made every three months: the Jews (a) have a notion that his mother was delivered of him at six months' end, and therefore when the other three months were up women usually go with child, she could hide him no longer, a birth of a child being then expected, and would be inquired about:
she took for him an ark of bulrushes; the word, according to Kimchi (b), signifies a kind of wood exceeding light, so Gersom and Ben Melech; an Arabic writer (c) calls it an ark of wood; it is generally taken to be the "papyrus" or reed of Egypt, which grew upon the banks of the Nile, and of which, many writers say, small vessels or little ships were made; see Gill on Isaiah 18:2.
and daubed it with slime and with pitch; with pitch without and slime within, as Jarchi observes; which being of a glutinous nature, made the rushes or reeds stick close together, and so kept out the water:
and put the child therein; committing it to the care and providence of God, hoping and believing that by some means or another it would be preserved; for this, no doubt, was done in faith, as was the hiding him three months, to which the apostle ascribes that, Hebrews 11:23.
and she laid it in the flags by the river's brink; among the sedge, weeds, and rushes, that grew upon the banks of the river Nile; there she laid it, that it might not be carried away with the stream of the river, and that it might be seen and taken up by somebody that would have compassion on it, and take care of it: the Arabic writers (d) say, that Jochebed made an ark of the papyrus, though in the law it is said to be of cork, and pitched within and without, and put the child into it, and laid it on the bank of the Nile, where the water was not so deep, by the city Tzan (or Zoan, that is, Tanis), which was the metropolis of the Tanitic nome; but very wrongly adds, that it might be killed by the dashing of the waves, and she might not see its death.
(a) Targum Jonah. & Jarchi in loc. (b) Sepher Shorash. rad. (c) Elmacius apud Hottinger. p. 402. (d) Patricides, p. 25. Elmacinus, p. 46. apud Hottinger. Smegma, c. 8. p. 400.

she took for him an ark of bulrushes--papyrus, a thick, strong, and tough reed.
slime--the mud of the Nile, which, when hardened, is very tenacious.
pitch--mineral tar. Boats of this description are seen daily floating on the surface of the river, with no other caulking than Nile mud (compare Isaiah 18:2), and they are perfectly watertight, unless the coating is forced off by stormy weather.
flags--a general term for sea or river weed. The chest was not, as is often represented, committed to the bosom of the water but laid on the bank, where it would naturally appear to have been drifted by the current and arrested by the reedy thicket. The spot is traditionally said to be the Isle of Rodah, near Old Cairo.

And when she could no longer hide him, she put him in an ark of bulrushes - By the river side. God put it into their hearts to do this, to bring about his own purposes: that Moses might by this means be brought into the hands of Pharaoh's daughter, and that by his deliverance, a specimen might be given of the deliverance of God's church.