Was God not able to break off branches from the tree? Paul seems to believe that those who DO such things will not enter the Kingdom of heaven.
Yes, some of the Jews were cut off from the tree because...
Romans 11 KJV
20 Well;
because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:
21 For if God spared not the natural branches, take heed lest he also spare not thee.
22 Behold therefore the goodness and severity of God:
on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off.
23 And they also,
if they abide not still in unbelief, shall be grafted in: for God is able to graft them in again.
So what I see is that they were cut off because they did not believe, those in the OT where Elias prays for the nation (which we see earlier in the chp. because they turned to idolatry). It is the same in the NT, not believing who Jesus is and in what He accomplished at the cross.
I don't see sin and works as the problem. I see relationship as the problem. Staying in a close relationship with God is what keeps us from sin and if we do sin we have an Advocate, to plead our case so we should confess and repent to stay close to our Advocate. And, staying in close relationship helps us to do the works that He would have us do, so we are not running around doing our own idea of what we think He wants us to do.
I think we can agree on this part?