1 Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it. 2 For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it. 3 For we which have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world. 4 For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works. 5 And in this place again, If they shall enter into my rest. 6 Seeing therefore it remaineth that some must enter therein, and they to whom it was first preached entered not in because of unbelief: 7 Again, he limiteth a certain day, saying in David, To day, after so long a time; as it is said, To day if ye will hear his voice, harden not your hearts. 8 For if Jesus had given them rest, then would he not afterward have spoken of another day. 9 There remaineth therefore a rest to the people of God. 10 For he that is entered into his rest, he also hath ceased from his own works, as God did from his. 11 Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief. 12 For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart. 13 Neither is there any creature that is not manifest in his sight: but all things are naked and opened unto the eyes of him with whom we have to do. 14 Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession. 15 For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin. 16 Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need.
[AD 407] John Chrysostom on Hebrews 3:16-4:2
[Hebrews 4:1-2] "Let us fear lest a promise being left us of entering into His rest, any of you should seem to come short of it; for to us was the Gospel preached as well as unto them when it is said, Today if you hear His voice" (for "Today" is "at every time" ).
Then [he adds] "but the word of hearing did not profit them, as they were not mixed by faith with them that heard." How did it not profit? Then wishing to alarm them, he shows the same thing by what he says:
[Hebrews 3:16-19] "For some when they had heard did provoke, howbeit not all that came out of Egypt by Moses: And with whom was He grieved forty years? Was it not with them that had sinned, whose carcasses fell in the wilderness? And to whom swear He that they should not enter into His rest, but to them that believed not? So we see, that they could not enter in because of unbelief." After again repeating the testimony, he adds also the question, which makes the argument clear. For he said (he repeats), "Today if you hear His voice, harden not your hearts, as in the provocation." Of whom does he speak (he says) [as] having been hardened? Of whom [as] not believing? Is it not of the Jews?
Now what he says is to this effect. They also heard, as we hear: but no profit came to them. Do not suppose then that by "hearing" what is proclaimed ye will be profited; seeing that they also heard, but derived no benefit because they did not believe.
Caleb then and Joshua, because they agreed not with those who did not believe, escaped the vengeance that was sent forth against them. And see how admirably he said, not, They did not agree, but, "they were not mixed" — that is, they stood apart, but not factiously when all the others had one and the same mind. Here it seems to me that a faction too is hinted at.