15 looking carefully lest anyone fall short of the grace of God; lest any root of bitterness springing up cause trouble, and by this many become defiled;
This verse is a warning to those not flourishing in the grace of God. Reversionism will cause a person to stagnate in Christian living.
15 looking carefully [exercise oversight]
When it comes to falling short of the grace of God, Christians need to take that seriously. They are to give serious attention to living at peace with others because, if they do not, then it may cause both internal and external trouble.
In considering the need to pursue peace with those tending toward reversionism, there was a need to give oversight to the problem. The words “looking carefully” mean to oversee; the idea is to provide oversight to believers with a tendency to disunity (1 Pe 5:2—same Greek word as our verse).
There are three “lest” clauses in verses 15 and 16, which warn of problems that could enter a congregation.
fall short of the grace of God;
The Greek word for “fall short” means to miss or fail to reach the goal (He 4:1). The “grace of God” in the context of the book of Hebrews refers to the Hebrew believer who intended to revert to Judaism. By doing this, they would fall short of the work of Christ on the cross.
“Fall short” has nothing to do with apostasy. The simple idea is to not reach a goal. The readers of Hebrews had gone so far in their understanding of what Christ did on the cross, but they fell short of comprehending the “grace of God.” They did not understand the finished work of Christ; they still operated under the Judaic Mosaic law.
The idea of “grace” is that God is the Provider of benefits for the believers. Christians often fail to appropriate God’s full blessings. God’s grace does not fail, but Christians fail to appropriate His grace for daily living.
lest any root of bitterness
“Root” is that which produces the fruit of a plant. The problem was not allowing oneself to reckon on God’s provision of righteousness by grace. It wants to produce a righteousness of its own. This is the hardening of Hebrew Christians earlier in Hebrews (He 3:7, 12–13; 4:7). These people had a “root of bitterness” toward fellow Christians. That root of bitterness poisoned other people.
springing up cause trouble,
Bitterness will affect other people when it springs up from an attitude. Anyone who introduces the “lest” issue will cause problems for any congregation. This believer will cause trouble among God’s people.
and by this many become defiled;
“Defiled” carries the idea of contamination. People in reversionism introduce an insidious or corroding dynamic into the church (Ti 1:15). It will spread the poison of bitterness among Christians. Bitterness always spoils productive Christian living.
The failure of one affects many.
Christians are to take into account the relationship of others with God. It is one thing to be circumspect about our behavior, but we must care about the conduct of others as well. Others may not pursue peace and sanctification. We need to help each other on that pathway.
Christians are to give serious attention to their attitude toward people with whom they conflict; that is, people with whom they pursued peace but who rejected that offer of friendship. There is the possibility of chain-reaction sinning. One sin can become the cause of other sinning. The “root” fixed in the defiled soul can spring up and infect others. This is especially true of bitterness. This sin can ignite sin in others because it is contagious.