Numbering the multitude, etc. As the gathering together of the people of whom the Psalmist spoke might appear to be an impossibility, there seems some ground for the opinion of those who think that he confirms it in this verse. The connection they give to the Psalmist's words is this -- that as it is at least not more difficult to gather men together who are outcast and scattered, than to number the stars, there was no reason why the wandering exile Israelites should despair of their return, provided they should resort with one consent to God as their only head. There is some probability, too, in the conjecture that the Psalmist may allude to that promise -- "Look now towards the stars of heaven, if thou canst tell them, so shall thy seed be." (Genesis 15:5.) But as the Psalmist immediately afterwards treats of the order of things in nature generally, the simplest rendering, I think, is to understand this verse with reference to the admirable work of God to be seen in the heavens, where we behold his matchless wisdom, in regulating, without one degree of aberration, the manifold, complex, winding courses of the stars. To each of them he assigns its fixed and distinct office, and in all the multitude there is no confusion. He therefore exclaims immediately -- Great is God, and boundless, both in power and understanding. We learn from this that there cannot be greater folly than to make our judgment the measure of God's works, displaying in these, as he often does, his incomprehensible power and wisdom.

He telleth the number of the stars - He counts them all. God only can do this. The stars are so numerous that no astronomer can count them; they lie so far in the depths of space, and are so remote from each other, that no man can be so presumptuous as to suppose that he has even seen any considerable part of them, even by the aid of the most powerful telescopes.
He calleth them all by their names - As if each one had a name, and God could call them forth one by one by their names, like the muster-roll of an army. This language seems to be taken from Isaiah 40:26 : "Lift up your eyes on high, and behold who hath created these things, that bringeth out their host by numbers; he calleth them all by names, by the greatness of his might, for that he is strong in power; not one faileth." See the notes at that passage.

He telleth the number of the stars - He whose knowledge is so exact as to tell every star in heaven, can be under no difficulty to find out and collect all the scattered exiles of Israel.

He (d) telleth the number of the stars; he calleth them all by [their] names.
(d) Though it seems incredible to man, that God should assemble his Church, being so dispersed, yet nothing can be too hard to him that can number and name all the stars.

He telleth the number of the stars,.... Which no man can do exactly; see Genesis 15:5; the ancient astronomers pretended to tell them, as Aratus and Eudoxus (o), and fixed their number at a thousand and some odd; but then these were only such as were of some magnitude and influence, and such as commonly appeared; but since the use of telescopes many are seen which were not before; and especially those clusters of them in the Milky Way cannot be distinctly discerned and told; but the Lord that made them can tell their exact number. Aben Ezra thinks this is said with respect to the outcasts of Israel scattered throughout the whole earth, as the stars are in the upper orb; and that as the Lord knows the one, he knows the other; which is not amiss, especially spiritually understood;
he calleth them all by their names; not that he calls one Jupiter and another Verus, &c. as the Heathens have done; but the sense is, that he has as perfect, distinct, and exact knowledge of them, as we have of any persons or things that we can call by name, and more so; see Isaiah 40:26. This may be applied to the saints, who are like to stars for the light they receive from Christ the sun of righteousness, and are a number which no man can number; but Christ knows them all distinctly and exactly, and can call them by name, and holds them in his right hand, and will preserve them; and they shall shine for ever like stars, yea, like the sun in the kingdom of his Father; so Arama interprets this of the righteous, who are compared to stars; see Daniel 12:4.
(o) Vid. Augustin de Civ. Dei, l. 16. c. 23.

God's power in nature (Isaiah 40:26-28, and often) is presented as a pledge of His power to help His people.
telleth . . . stars--what no man can do (Genesis 15:5).

Calleth them - He exactly knows them as we do those whom we can call by name.