Albert Barnes Commentary Revelation 2:23

"And I will kill her children with death; and all the churches shall know that I am he that searcheth the reins and hearts: and I will give unto each one of you according to your works." — Revelation 2:23 (ASV)

And I will kill her children with death. This is a strong Hebraistic mode of expression, meaning that he would certainly destroy them. The question has been raised whether the word children here is to be taken literally or figuratively. The word itself could admit of either interpretation, and there is nothing in the connection by which its meaning here can be determined.

If it is to be taken literally, it is consistent with what is often threatened in the Scriptures: that children will be visited with calamity for the sins of their parents, and with what often occurs in fact—that they do suffer in this way. For it is not uncommon for whole families to be made desolate because of the sin and folly of a parent .

If it is to be taken figuratively, then it refers to those who had imbibed her doctrines and who, of course, would suffer in the punishment that would follow from the propagation of such doctrines. The word death here seems to refer to some severe judgment—by plague, famine, or sword—by which they would be cut off. And all the churches shall know, etc. That is, the purpose of this judgment will be so apparent that it will convince everyone that I know what is in the hearts of men—even the secret acts of wickedness concealed from human view.

I am he which searcheth the reins and hearts. This is clearly a claim to omniscience; and as it is the Lord Jesus who speaks in all these epistles, it is full proof that he claims this for himself. There is nothing that more clearly pertains to God than the power of searching the heart, and nothing that is more constantly claimed by him as his unique prerogative (1 Chronicles 28:19; Psalms 7:9; Psalms 11:4; Psalms 44:21; Psalms 139:2; Proverbs 15:3; Jeremiah 11:20; Jeremiah 17:10; Jeremiah 20:12; Jeremiah 32:19; Hebrews 4:13).

The word reins—nefrouv—means, literally, the kidney, and is commonly used in the plural to denote the kidneys or the loins. In the Scriptures, it is used to denote the innermost mind, the secrets of the soul—probably because the parts referred to by the word are as hidden as any other part of the body and seem to be the repository of the more secret affections of the mind. It should not be supposed that the Scriptures teach that the reins are the real seat of any of the affections or passions; but there is no more impropriety in using the term in a popular sense than there is in using the word heart, which all continue to use to denote the seat of love.

And I will give unto every one of you according to your works. To every one of you—not only to those who have embraced these opinions, but to all the church. This is the consistent rule laid down in the Bible by which God will judge men.