See to it that no one falls short of the grace of God and that no bitter root grows up to cause trouble and defile many. 

Look after each other so that none of you fails to receive the grace of God. Watch out that no poisonous root of bitterness grows up to trouble you, corrupting many. (New Living Translation)

To fall short of God’s grace is to fail to avail ourselves of it.

Hebrews 4:16 says:

”Let us then approach God’s throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.”

Whatever our trials, tests, temptations, challenges, difficulties etc, the grace of God is available to enable us to endure, resist, turn away, press on – whatever it is we need to do to ‘pursue holiness’.

‘God’s grace does not fail, but we can fail to take advantage of His grace. At the end of the chapter, there is another emphasis on grace (Heb.12:28).’ Warren W. Wiersbe: ‘New Testament Commentary’, p.841.

The way the ‘New Living Translation’ puts this, we see that we can remind each other of the resources richly available in Christ, and help one another lay hold of them. ”Peace” is important (v.14) because fellowship is crucial to growth in holiness. As Christians, we are to be watchful of the spiritual welfare of our brothers and sisters in the church.

One thing that can happen when someone fails to receive and rely on God’s grace, is that they can become a bitter root and cause trouble for the entire congregation. David Peterson, in the ‘New Bible Commentary’, says that the imagery recalls Dt.29:18, where Moses warned that bitterness could be spread throughout the entire community of God’s people by one rebellious member.

 Keep a sharp eye out for weeds of bitter discontent. A thistle or two gone to seed can ruin a whole garden in no time. (The Message).

It is possible for Christians to disagree without being disagreeable. But where bitterness starts to mark the debate, and then fuel and control it…in that direction lies damage, and even, possibly, ruin.