1 Cor 1:24
23 But we preach Christ crucified, unto the Jews a stumblingblock, and unto the Greeks foolishness;
Two of the most hated and resisted Truths of the Gospel, a stumblingblock to the natural, carnal mind of man are #1 Election of Grace !
First of all election of grace is eternal in that God chose certain individuals, a remnant from mankind in Christ Jesus before the foundation of the world Eph 1:4
4 According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:
This Grace of Election was given them In Christ Jesus before the world began 2 Tim 1:9
9 Who hath saved us, and called us with an holy calling, not according to our works, but according to his own purpose and grace, which was given us in Christ Jesus before the world began,
Purpose and Grace both refer to election. The Election of Grace Rom 11:5
5 Even so then at this present time also there is a remnant according to the election of grace.
11 (For the children being not yet born, neither having done any good or evil, that the purpose of God according to election might stand, not of works, but of him that calleth)
Now Two things about this eternal election of Grace that men war against. #1. Its always only for a remnant of men, and not all men without exception, hence Paul calls the elect among the jews a remnant Rom 11:5
5 Even so then at this present time also there is a remnant according to the election of grace.
Now even in the OT concerning the jews, Isaiah writes of them Isa 1:9
9 Except the Lord of hosts had left unto us a very small remnant, we should have been as Sodom, and we should have been like unto Gomorrah.
Thats why Jesus says of the nation of Israel, under National Covenet this Matt 22:14
For many are called, but few are chosen.
See, not all ethnic jews that comprised ethnic Israel under the OC, were chosen of God only a few of them, out of the many of that nation !
So one of the stumblingblock truths of election of Grace, or salvation by grace, it is the fact that its limited to only a remnant, whether a remnant amongst the jews or a remnant amongst the gentiles ! Sorry, but all without exception cannot be of the election of Grace !