But we know that the judgment of God, etc. The design of Paul is to shake off from hypocrites their self-complacencies, that they may not think that they can really gain any thing, though they be applauded by the world, and though they regard themselves guiltless; for a far different trial awaits them in heaven. But as he charges them with inward impurity, which, being hid from the eyes of men, cannot be proved and convicted by human testimonies, he summons them to the tribunal of God, to whom darkness itself is not hid, and by whose judgment the case of sinners, be they willing or unwilling, must be determined. Moreover, the truth of judgment will in two ways appear, because God will punish sin without any respect of persons, in whomsoever it will be found; and he will not heed outward appearances, nor be satisfied with any outward work, except what has proceeded from real sincerity of heart. It hence follows, that the mask of feigned sanctity will not prevent him from visiting secret wickedness with judgment. It is, no doubt, a Hebrew idiom; for truth in Hebrew means often the inward integrity of the heart, and thus stands opposed not only to gross falsehood, but also to the outward appearance of good works. And then only are hypocrites awakened, when they are told that God will take an account, not only of their disguised righteousness, but also of their secret motives and feelings. [1]

Footnotes

1 - "According to truth" -- kata aletheian, means, according to the true state of the case, without any partiality, or according to what is just and equitable; so Grotius takes it. Its corresponding word in Hebrew, 'mt, is sometimes rendered dikaiosunm, It is found opposed to adikia in 1-Corinthians 13:6. The expression here may be deemed to be the same in meaning with dikaiokrisia -- righteous judgment, in verse 5. -- Ed.

But we are sure - Greek, "We know." That is, it is the common and admitted sentiment of mankind. It is known and believed by people generally that God will punish such crimes. It is implied in this declaration that this was known to the Jews, and it was particularly to the purpose of the apostle so to express himself as to include the Jews. They knew it because it was everywhere taught in the Old Testament, and it was the acknowledged doctrine of the nation. The design of the apostle here, says Calvin, is to take away the subterfuges of the hypocrite, lest he should pride himself if he obtained the praise of human beings, for a far more important trial awaited him at the bar of God. Outwardly he might appear well to people; but God searched the heart, and saw the secret as well as the open deeds of people, and they who practiced secretly what they condemned openly, could not expect to escape the righteous judgment of God. God, without respect of persons would punish wickedness, whether it was open, as among the Gentiles, or whether it was concealed under the guise of great regard for religion, as among the Jews.
The judgment of God - That God condemns it, and will punish it. He regards those who do these things as guilty, and will treat them accordingly.
According to truth - This expression is capable of two meanings. The Hebrews sometimes use it to denote truly or certainly. God will certainly judge and punish such deeds. Another meaning, which is probably the correct one here, is that God will judge those who are guilty of such things, not according to appearance, but in integrity, and with righteousness. He will judge people according to the real nature of their conduct, and not as their conduct may appear to people. The secret, as well as the open sinner therefore; the hypocrite, as well as the abandoned profligate, must expect to be judged according to their true character. This meaning comports with the design of the apostle, which is to show that the Jew, who secretly and hypocritically did the very things which he condemned in the Gentile, could not escape the righteous judgment of God.
Against him - That is, against every man, no matter of what age or nation.
Which commit such things - The crimes enumerated in Romans. 1. The apostle is not to be understood as affirming that each and every individual among the Jews was guilty of the specific crimes charged on the pagan, but that they were as a people inclined to the same things. Even where they might be externally moral, they might be guilty of cherishing evil desires in their hearts, and thus be guilty of the offence, Matthew 5:28. When people desire to do evil, and are prevented by the providence of God, it is right to punish them for their evil intentions. The fact that God, prevents them from carrying their evil purposes into execution, does not constitute a difference between their real character and the character of those who are suffered to act out their wicked designs.

We are sure that the judgment of God, etc. - God is impartial, and will punish sin wheresoever he finds it. Transgression in a Jew is not less criminal than iniquity in a Gentile.

But we (a) are sure that the judgment of God is according to (b) truth against them which commit such things.
(a) Paul alleges no places of scripture, for he reasons generally against all men: but he brings reasons such that every man is persuaded by them in his mind, so that the devil himself is not able to completely pluck them out.
(b) Considering and judging things correctly, and not by any outward show.

But we are sure that the judgment of God,.... By "the judgment of God", is not meant what is exercised on and towards men in this life, but what will follow after death; which is called judgment to come, is represented as certain, will be universal as to persons and things, and is here called "the judgment of God", in opposition to the judgment of men; and because it will be carried on by God only, who is omniscient and omnipotent, and will be definitive: this is and will be,
according to truth, against them which commit such things; in opposition to all hypocrisy and unrighteousness: and it may design the law and light of nature by which the Gentiles, the law of Moses by which the Jews, and the Gospel of Christ by which all have enjoyed the Gospel revelation, will be judged; or the truth of their own consciences in them all: now we may be sure of this judgment; and of its being according to truth, from reason, from Scripture, and from the being and perfections of God.

For we know - Without thy teaching That the judgment of God - Not thine, who exceptest thyself from its sentence. Is according to truth - Is just, making no exception, Romans 2:5-6, Romans 2:11; and reaches the heart as well as the life, Romans 2:16.