<p>12:15- see on 1 Jn. 2:28.</p><p><em>See to it that no one comes short of the grace of God; that no root of bitterness springing up causes trouble, and by it many are defiled</em>- The bitter root refers to a poisonous plant growing up in the path to the Kingdom spoken of in :13 and :14. It is the responsibility of each of us, and not just the elders, to ensure that none fail of God's grace; and the Judaist menace was taking people away from that grace. The bitter rooted plant could lead to many being defiled, a term with cultic overtones. Defilement meant that the defiled could no longer serve in the temple cult, and the holiness / imputed righteousness which was to be followed after and attained by grace would then be made null and void. The quotation is from Dt. 29:18 LXX which speaks of a false teacher arising and inviting God's people to serve the idols of the world around them. This is how Paul presented the Judaizers with their appeal to the Jerusalem Christians to return to the apparent monotheism of the temple cult. It was no more than idolatry; and we noted on 1:1 that Paul was deeply touched by Stephen's address in Acts 7 and reflects it in his reasoning to the Hebrew Christians. Stephen too had by inference made this same point. And this is how Judaism should be seen by Christians today.</p>