For some, when they had heard, etc. David spoke of the fathers as though that whole generation were unbelieving; but it appears that some who truly feared God mingled with the wicked. The apostle mentions this to modify what had been more severely said by David, in order that we may know that the word is preached to all for this end, that all may obey it with one consent, and that the whole people were justly condemned for unbelief, when the body was torn and mutilated by the defection of the greatest part. But by saying that some provoked, while yet they were by far the greatest part, this object was not only to avoid giving offense, but also to encourage the Jews to imitate those who believed; as though he had said, "As God forbids you to follow the unbelief of the fathers, so he sets before you other fathers whose faith is to be your example". Thus is mitigated what otherwise might have appeared too hard; that is, had they been commanded wholly to dissent from their fathers. To come out by Moses, means by the hand of Moses, for he was the minister of their deliverance. But there is an implied comparison between the benefit which God had bestowed on them by Moses, and the participation of Christ previously mentioned.

For some - Some of the Hebrews who came out of Egypt. The truth was that a large proportion of them rebelled against God, and provoked him to indignation. It is somewhat remarkable that though "all" the Hebrews seem to have joined in the provocation - except a very small number - Paul should have used language which would seem to imply that the number which rebelled was comparatively small. Another version, therefore, has been given to this passage by some of the most eminent critics, consisting merely in a change in the punctuation, by which a different view is given of the whole sentence. According to this, it would be a question, and would mean, "But who were they who when they had heard did provoke? Were they not all indeed who came out of Egypt under Moses? And with whom was He angry for 40 years? Was it not with those who sinned, whose carcasses fell in the wilderness?" This version was adopted by Chrysostom, Theodoret, and others of the Fathers; and is adopted by Rosenmuller, Clarke, Stuart, Pyle, and some others. In favor of it, it may be alleged:
(1) that the Greek will bear it, all the change required being in the punctuation;
(2) that it avoids the difficulty which exists in the other interpretation of supposing the apostle to imply that but few of them rebelled, when the truth was that it was nearly all;
(3) it thus accords with the remainder of the exhortation, which consists in a series of questions; and,
(4) it agrees with the scope and design of the whole.
The object was not to state that it was not all who came out of Egypt that rebelled, or that the number was small, but that the great body of them rebelled and fell in the wilderness, and that Christians should be admonished by their example. These reasons seem to be so strong as to make it probable that this is the true construction, and the sense then will be, "For who were they that having heard did provoke? Were they not all who came out of Egypt under Moses?"
When they had heard - Had heard God speaking to them, and giving them his commands.
Did provoke - Provoked him to anger; or their conduct was such as was suited to produce indignation; see the note on Hebrews 3:8.
Howbeit - Αλλά Alla. "But." This particle "in a series of questions, and standing at the head of a question, means "but, further." It serves to connect, and give intensity to the interrogation" - Stuart. Paul means to ask with emphasis whether the great mass of those who came out of Egypt did not apostatize? At the same time he means to intimate that there is no security that they who have witnessed - remarkable manifestations of the greatness of God, and who have partaken of extraordinary mercies, will not apostatize and perish. As the Hebrews, who heard God speak from Mount Sinai, revolted and perished, so it is possible that they who witness the mercies of God in redemption, may be in danger of abusing all those mercies, and of perishing. By the example, therefore, of the disobedient Israelites, he would admonish professed Christians of their danger.
Not all - According to the interpretation proposed above, "Were they not all who came out of Egypt?" Or "did not all who came out of Egypt?" The word "all" here is not to be taken in the strict sense, It is often used to denote the great body; a large proportion; or vast multitudes. Thus, it is used in Matthew 3:5, "Then went out to him Jerusalem, and all Judea, and all the region round about Jordan." So in John 3:26, "The same baptizeth, and all people came to him." So Philippians 2:21, "For all seek their own;" 2-Corinthians 3:2, "Ye are our epistle, known and read of all men." "In fact" there were two exceptions - and but two - of the adults who came out of Egypt - Caleb and Joshua; Numbers 14:30. All the others complained against the Lord, and were prohibited from entering the promised land. Of the great multitudes who came out of Egypt, and who murmured, the exception was so small that the apostle had no scruple in saying in general that they were all rebellious.

For some, when they had heard, did provoke - There is a various reading here, which consists merely in the different placing of an accent, and yet gives the whole passage a different turn: - τινες, from τις, who, if read with the accent on the epsilon, τινὲς, is the plural indefinite, and signifies some, as in our translation; if read with the accent on the iota, τίνες, it has an interrogative meaning; and, according to this, the whole clause, τίνες γαρ ακουσαντες παρεπικραναν; But who were those hearers who did bitterly provoke? αλλ' ου παντες οἱ εξελθοντες εξ Αιγυπτου δια Μωσεως; Were they not all they who came out of the land of Egypt by Moses? Or, the whole clause may be read with one interrogation: But who were those hearers that did bitterly provoke, but all those who came out of Egypt by Moses? This mode of reading is followed by some editions, and by Chrysostom and Theodoret, and by several learned moderns. It is more likely that this is the true reading, as all that follows to the end of the 18th verse is a series of interrogations.
Should it be said that all did not provoke, for Joshua and Caleb are expressly excepted; I answer, that the term all may be with great propriety used, when out of many hundreds of thousands only two persons were found who continued faithful. To these also we may add the priests and the whole tribe of Levi, who, it is very likely, did not provoke; for, as Dr. Macknight very properly remarks, they were not of the number of those who were to fight their way into Canaan, being entirely devoted to the service of the sanctuary. See Numbers 1:3, Numbers 1:45, and Numbers 1:49. And therefore what remained of them after forty years, no doubt, entered Canaan; for it appears from Numbers 34:17, and Joshua 24:33, that Eleazar, the son of Aaron, was one of those who did take possession of Canaan. Should it be still said our version appears to be most proper, because all did not provoke; it may be answered, that the common reading, τινὲς, some, is too contracted in its meaning to comprehend the hundreds of thousands who did rebel.

For some, when, they had heard,.... The Arabic version adds, "his voice"; the law on Mount Sinai; the voice of words, with the voices and thunderings that attended it; the book of the covenant read; the whole system of laws and ordinances delivered to Moses, and by him to them; and also the Gospel, for that was preached to the Israelites in the wilderness, and heard by them; as appears from Hebrews 4:2 and which seems chiefly intended: and yet some of the hearers of it
did provoke; not only Moses, to speak unadvisedly with his lips; but they provoked Jehovah himself, and the angel of his presence, and his Holy Spirit, by their idolatry, ingratitude, and unbelief: and the aggravation of their sin is, that they did it when they had heard the Gospel, and while they were hearing it; which shows that the Gospel may be heard to no advantage; as when it is heard in a careless and indifferent manner; when it makes no impression, takes no place, and has no root; when the world and the things of it are the great concern of the mind, while hearing it; when it is not attended with the power and Spirit of God; when it is not received in love, nor mixed with faith, nor put in practice: and hence the Gospel heard, comes to be an aggravation of men's condemnation:
howbeit not all that came out of Egypt by Moses; that is, they did not all provoke, but some did; which is another aggravation of their sin; they were just come out of Egyptian bondage; brought out of it by the Lord, with the mighty and outstretched arm of his power; and yet they provoked him: and this was done by Moses; by the hand of Moses, as the Syriac version renders it; by his means, by him as an instrument; and yet they provoked him: but however all did not, yet these were but few; it seems only Caleb and Joshua, out of six hundred thousand; God will have a few to serve him in the worst of times.

For some--rather interrogatively, "For WHO was it that, when they had heard (referring to 'if ye will hear,' Hebrews 3:15), did provoke (God)?" The "For" implies, Ye need to take heed against unbelief: for, was it not because of unbelief that all our fathers were excluded (Ezekiel 2:3)? "Some," and "not all," would be a faint way of putting his argument, when his object is to show the universality of the evil. Not merely some, but all the Israelites, for the solitary exceptions, Joshua and Caleb, are hardly to be taken into account in so general a statement. So Hebrews 3:17-18, are interrogative: (1) the beginning of the provocation, soon after the departure from Egypt, is marked in Hebrews 3:16; (2) the forty years of it in the wilderness, Hebrews 3:17; (3) the denial of entrance into the land of rest, Hebrews 3:18. Compare Note, see on 1-Corinthians 10:5, "with the majority of them God was displeased."
howbeit--"Nay (why need I put the question?), was it not all that came out of Egypt?" (Exodus 17:1-2).
by Moses--by the instrumentality of Moses as their leader.

Were they not all that came out of Egypt - An awful consideration! The whole elect people of God (a very few excepted) provoked God presently after their great deliverance, continued to grieve his Spirit for forty years, and perished in their sin!