SCRIPTURE Romans 11:17–24 “And if some of the branches be broken off, and thou, being a wild olive tree, wert grafted in among them, and with them partakest of the root and fatness of the olive tree; Boast not against the branches.  But if thou boast, thou bearest not the root, but the root thee.  Thou wilt say then, the branches were broken off, that I might be grafted in.  Well; because of unbelief they were broken off, and thou standest by faith.  Be not highminded, but fear: For if God spared not the natural branches, take heed lest he also spare not thee.  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.  And they also, if they abide not still in unbelief, shall be grafted in: for God is able to graft them in again.  For if thou wert cut out of the olive tree which is wild by nature, and wert grafted contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be grafted into their own olive tree?”   

COMMENTARY Clearly shows that God will not spare branches (believers) who don’t continue to stand by faith, but will cut them off.  The branches grafted in (Gentiles) were not a part of the natural tree (Israel), but could later be cut off, indicating that they could be again separated from the root, which is Christ, meaning they could lose their salvation.  Again, this is another warning from Christ Himself that salvation can be lost; that we branches can be cut off.   We are told here to not be highminded, but fear.  Fear (Greek phobéō) here is not respect or awe; it is to fear, be afraid; very often absolutely to be struck with fear, to be seized with alarm.