Inasmuch as what may be known of God, etc. He thus designates what it behoves us to know of God; and he means all that appertains to the setting forth of the glory of the Lord, or, which is the same thing, whatever ought to move and excite us to glorify God. And by this expression he intimates, that God in his greatness can by no means be fully comprehended by us, and that there are certain limits within which men ought to confine themselves, inasmuch as God accommodates to our small capacities what he testifies of himself. Insane then are all they who seek to know of themselves what God is: for the Spirit, the teacher of perfect wisdom, does not in vain invite our attention to what may be known, to gnoston; and by what means this is known, he immediately explains. And he said, in them rather than to them, for the sake of greater emphasis: for though the Apostle adopts everywhere Hebrew phrases, and v, beth, is often redundant in that language, yet he seems here to have intended to indicate a manifestation, by which they might be so closely pressed, that they could not evade; for every one of us undoubtedly finds it to be engraven on his own heart, [1] By saying, that God has made it manifest, he means, that man was created to be a spectator of this formed world, and that eyes were given him, that he might, by looking on so beautiful a picture, be led up to the Author himself.

Footnotes

1 - Some take en autois, to mean among them, i.e., as Stuart says, "in the midst of them, or before their eyes," that is, in the visible world; though many refer it with Calvin, to the moral sense, and that the expression is the same with "written in their hearts," in Romans 2:15. -- Ed.

Because - The apostle proceeds to show how it was that the pagan hindered the truth by their iniquity. This he does by showing that the truth might be known by the works of creation; and that nothing but their iniquity prevented it.
That which may be known of God - That which is "knowable" concerning God. The expression implies that there may be many things concerning God which cannot be known. But there are also many things which may be ascertained. Such are his existence, and many of his attributes, his power, and wisdom, and justice, etc. The object of the apostle was not to say that every thing pertaining to God could be known by them, or that they could have as clear a view of him as if they had possessed a revelation. We must interpret the expression according to the object which he had in view. That was to show that so much might be known of God as to prove that they had no excuse for their crimes; or that God would be just in punishing them for their deeds. For this, it was needful only that his existence and his justice, or his determination to punish sin, should be known; and this, the apostle affirms, was known among them, and had been from the creation of the world. This expression. therefore, is not to be pressed as implying that they knew all that could be known about God, or that they knew as much as they who had a revelation; but that they knew enough to prove that they had no excuse for their sins.
Is manifest - Is known; is understood.
In them - "Among" them. So the preposition "in" is often used. It means that they had this knowledge; or it had been communicated to them. The great mass of the pagan world was indeed ignorant of the true God; but their leaders, or their philosophers, had this knowledge; see the note at Romans 1:21. But this was not true of the mass, or body of the people. Still it was true that this knowledge was in the possession of man, or was "among" the pagan world. and would have spread, had it not been for the love of sin.
God hath showed it to them - Compare John 1:9. He had endowed them with reason and conscience Romans 2:14-15; he had made them capable of seeing and investigating his works; he had spread before them the proofs of his wisdom, and goodness, and power, and had thus given them the means of learning his perfections and will.

That which may be known of God - Dr. Taylor paraphrases this and the following verse thus: "Although the Gentiles had no written revelation, yet what may be known of God is every where manifest among them, God having made a clear discovery of himself to them. For his being and perfections, invisible to our bodily eyes, have been, ever since the creation of the world, evidently to be seen, if attentively considered, in the visible beauty, order, and operations observable in the constitution and parts of the universe; especially his eternal power and universal dominion and providence: so that they cannot plead ignorance in excuse of their idolatry and wickedness."

(9) Because that which may be known of God is manifest in (c) them; for God hath shewed [it] unto them.
(9) By their ungodliness he proves that although all men have a most clear and evident mirror in which to behold the everlasting and almighty nature of God, even in his creatures, yet they have fallen away from those principles to most foolish and stupid ideas of their own brains, in their worship of God and of what God requires of them.
(c) In their hearts.

Because that which may be known of God,.... There are some things which could not be known of God by the light of nature; as a trinity of persons in the Godhead; the knowledge of God in Christ as Mediator; the God-man and Mediator Jesus Christ; his incarnation, sufferings, death, and resurrection; the will of God to save sinners by a crucified Jesus; the several peculiar doctrines of the Gospel, particularly the resurrection of the dead, and the manner of worshipping of God with acceptance: but then there are some things which may be known of God, without a revelation. Adam had a perfect knowledge of him; and his sons, though fallen, even the very Heathens have some notion of him, as that there is a God; and by the light of nature it might be known that there is but one God, who is glorious, full of majesty, and possessed of all perfections, as that he is all powerful, wise, good and righteous: and this
is manifest in them, or "to them"; by the light that is given them: it is light by which that which may be known of God is manifest; and this is the light of nature, which every man has that comes into the world; and this is internal, it is in him, in his mind and conscience, and is communicated to him by God, and that by infusion or inspiration; see Job 32:8;
for God hath showed it unto them; what may be known of him by that light; and which is assisted and may be improved by a consideration of the works of creation and Providence.

Because that which may be--rather, "which is."
known of God is manifest in them; for God hath showed it unto them--The sense of this pregnant statement the apostle proceeds to unfold in Romans 1:20.

For what is to be known of God - Those great principles which are indispensably necessary to be known. Is manifest in them; for God hath showed it to them - By the light which enlightens every man that cometh into the world.