A
Lets examine them..,,,
why were they rejected? They rejected Jesus. Many people raised in the church also reject Jesus and are just playing Church because of their parents faith forces them to attend.
Again if you believe a false gospel as the Jews did and reject the Gospel of grace...no matter how much you claim to love God and attend church, you will be a dead branch and be cut off.
pride is wrong. You should be humble before God...
Don't see anything about lose of salvation there.
It seems you are adding your spin to the commentary to support your doctrine that is not there.
Let's post some more commentaries that agree with me.
Gill's Exposition of the Entire Bible
For if God spared not the natural branches,.... That is, executed his righteous judgments, inflicted due punishment upon the Jews, unchurched them, and stripped them of those privileges they enjoyed in a church state; who were the natural descendants of Abraham; were naturally, and as born into the world, in a national church state and in that national covenant God made with that people; to whom belonged a national adoption, in which sense they were the sons of God, his firstborn; they were chosen by him as a special and peculiar people, to very great favours and privileges; they were Christ's own, he came of them according to the flesh, and was particularly sent unto them, and ministered among them; wherefore, if, at last, God did not spare this people, though he had for a long time done it, but stirred up all his wrath against them, they disbelieving his Son, rejecting and despising the Messiah, and salvation by him, this should awaken the fear, care, and caution of the Gentiles in a church state, lest if they behave not well, he should deal in like manner with them:take heed lest he also spare not thee; for whatever was done to the Jews in former or latter times, are written for the instruction and admonition of Gentiles; and the use they are to make thereof is, to be careful and cautious, lest by imbibing principles derogatory from the grace of God and glory of Christ, or by an unbecoming walk and conversation they provoke the Lord to unchurch them as he has done the Jews before them; and which they may the rather fear, since the Jews were the natural branches, and they formerly strangers and aliens.
Gill's Exposition of the Entire Bible
For if God spared not the natural branches,.... That is, executed his righteous judgments, inflicted due punishment upon the Jews, unchurched them, and stripped them of those privileges they enjoyed in a church state; who were the natural descendants of Abraham; were naturally, and as born into the world, in a national church state and in that national covenant God made with that people; to whom belonged a national adoption, in which sense they were the sons of God, his firstborn; they were chosen by him as a special and peculiar people, to very great favours and privileges; they were Christ's own, he came of them according to the flesh, and was particularly sent unto them, and ministered among them; wherefore, if, at last, God did not spare this people, though he had for a long time done it, but stirred up all his wrath against them, they disbelieving his Son, rejecting and despising the Messiah, and salvation by him, this should awaken the fear, care, and caution of the Gentiles in a church state, lest if they behave not well, he should deal in like manner with them:take heed lest he also spare not thee; for whatever was done to the Jews in former or latter times, are written for the instruction and admonition of Gentiles; and the use they are to make thereof is, to be careful and cautious, lest by imbibing principles derogatory from the grace of God and glory of Christ, or by an unbecoming walk and conversation they provoke the Lord to unchurch them as he has done the Jews before them; and which they may the rather fear, since the Jews were the natural branches, and they formerly strangers and aliens.
why were they rejected? They rejected Jesus. Many people raised in the church also reject Jesus and are just playing Church because of their parents faith forces them to attend.
Expositor's Greek Testament
Romans 11:21. As far as comparisons can be made at all in such things, the Jews had been more securely invested in the kingdom than the Gentiles. They were, in the language of the figure, not artificially grafted, but native branches, on the tree of God’s people; yet even that did not prevent Him from cutting off those who did not believe. And if He did not spare them, He will not spare Gentiles either, if in pride they fall from faith. On εἰ … οὐκ ἐφείσατο see Winer, 599 f. The true reading of the last word is φείσεται (not φείσηται), but Weiss would retain μήπως (see crit. note) even with this future, and supply the missing link of thought from φοβοῦ: one may fear that he will not, etc. The ironical reserve of this (though the future makes the thing to be feared as certain as possible) is quite Pauline, and the μήπως ([7] [8] [9] [10]) may be genuine.
Barnes notes
For if God ... - If God did not refrain from rejecting the Jews who became unbelievers, assuredly he will not refrain from rejecting you in the same circumstances. It may be supposed that he will be quite as ready to reject the ingrafted branches, as to cast off those which belonged to the parent stock. The situation of the Gentiles is not such as to give them any security over the condition of the rejected Jew.
Romans 11:21. As far as comparisons can be made at all in such things, the Jews had been more securely invested in the kingdom than the Gentiles. They were, in the language of the figure, not artificially grafted, but native branches, on the tree of God’s people; yet even that did not prevent Him from cutting off those who did not believe. And if He did not spare them, He will not spare Gentiles either, if in pride they fall from faith. On εἰ … οὐκ ἐφείσατο see Winer, 599 f. The true reading of the last word is φείσεται (not φείσηται), but Weiss would retain μήπως (see crit. note) even with this future, and supply the missing link of thought from φοβοῦ: one may fear that he will not, etc. The ironical reserve of this (though the future makes the thing to be feared as certain as possible) is quite Pauline, and the μήπως ([7] [8] [9] [10]) may be genuine.
Barnes notes
For if God ... - If God did not refrain from rejecting the Jews who became unbelievers, assuredly he will not refrain from rejecting you in the same circumstances. It may be supposed that he will be quite as ready to reject the ingrafted branches, as to cast off those which belonged to the parent stock. The situation of the Gentiles is not such as to give them any security over the condition of the rejected Jew.
Again if you believe a false gospel as the Jews did and reject the Gospel of grace...no matter how much you claim to love God and attend church, you will be a dead branch and be cut off.
Pulpit Commentary Homiletics
II. But this very position was fraught with danger. "Glory not;" "Thou standest by thy faith." The danger of false pride was not an imaginary one; Gentiles probably did glory over the Jews. Nay, do they not glory still over these "unbelievers"? Do they not sometimes persecute them even to death? But how false was the pride! They were only grafted branches, borne by the ancient root of Israel. And yet they deported themselves with such consequence, and affected to despise their neighbour branches, as well as those that had been broken off. Another danger was involved in this: false, uncharitable pride was perilously near to a damnable unbelief; it was indeed that unbelief begun. Why had these branches been broken from the ancient tree? "Because of their unbelief." Was not the same excision impending over unbelief still? Instead, then, of pride, let them cherish a holy fear, and walk humbly with their God. For most surely, if God spared not the natural branches, neither would he spare them.
II. But this very position was fraught with danger. "Glory not;" "Thou standest by thy faith." The danger of false pride was not an imaginary one; Gentiles probably did glory over the Jews. Nay, do they not glory still over these "unbelievers"? Do they not sometimes persecute them even to death? But how false was the pride! They were only grafted branches, borne by the ancient root of Israel. And yet they deported themselves with such consequence, and affected to despise their neighbour branches, as well as those that had been broken off. Another danger was involved in this: false, uncharitable pride was perilously near to a damnable unbelief; it was indeed that unbelief begun. Why had these branches been broken from the ancient tree? "Because of their unbelief." Was not the same excision impending over unbelief still? Instead, then, of pride, let them cherish a holy fear, and walk humbly with their God. For most surely, if God spared not the natural branches, neither would he spare them.
Don't see anything about lose of salvation there.
It seems you are adding your spin to the commentary to support your doctrine that is not there.