Doth the eagle mount up at thy command? - Margin, as in Hebrew, "by thy mouth." The meaning is, that Job had not power to direct or order the eagle in his lofty flight. The eagle has always been celebrated for the height to which it ascends. When Ramond had reached the summit of Mount Perdu, the highest of the Pyrenees, he perceived no living creature but an eagle which passed above him, flying with inconceivable rapidity in direct opposition to a furious wind. "Edin. Ency." "Of all animals, the eagle flies highest; and from thence the ancients have given him the epithet of "the bird of heaven." "Goldsmith." What is particularly worth remarking here is, the accuracy with which the descriptions in Job are made. If these are any indications of the progress of the knowledge of Natural History, that science could not have been then in its infancy. Just the things are adverted to here which all the investigations of subsequent ages have shown to characterize the classes of the feathered creation referred to.
And make her nest on high - "The nest of the eagle is usually built in the most inaccessible cliff of the rock, and often shielded from the weather by some jutting crag that hangs over it." "Goldsmith." "It is usually placed horizontally, in the hollow or fissure, of some high and abrupt rock, and is constructed of sticks of five or six feet in length, interlaced with pliant twigs, and covered with layers of rushes, heath, or moss. Unless destroyed by some accident, it is supposed to suffice, with occasional repairs, for the same couple during their lives." "Edin. Ency."

Doth the eagle mount up - The eagle is said to be of so acute a sight, that when she is so high in the air that men cannot see her, she can discern a small fish in the water! See on Job 39:29 (note).

Doth the eagle mount up at thy command,.... No; but by an instinct which God has placed in it, and a capacity he has given it above all other birds. They take a circuit in their flight, and bend about before they soar aloft: but the eagle steers its course directly upwards towards heaven, till out of sight; and, as Apuleius says (p), up to the clouds, where it rains and snows, and beyond which there is no place for thunder and lightning;
and make her nest on high? so the philosopher says (q); eagles make their nests not in plains, but in high places, especially in cragged rocks, as in Job 39:28.
(p) Florida 1. (q) Aristot. Hist. Animal. l. 9. c. 32.

eagle--It flies highest of all birds: thence called "the bird of heaven."

Mount - Flies directly upward 'till she be out of thy sight; which no other bird can do.