The book of Hebrews was written to the Jews who were kind of giving up in their faith in Christ. Their faith in the promises of God and the uniqueness of Christ was diminishing. The Hebrew writer tries to remind them about the greatness of Christ and His uniqueness.
12 See to it, brothers, that none of you has a sinful, unbelieving heart that turns away from the living God.
13 But encourage one another daily, as long as it is called Today, so that none of you may be hardened by sin's deceitfulness.
This is a Scripture which we are all very familiar with. But reading it through the context of what was happening throws some light. The writer is reminding them about the Israelites and their journey to the Promised Land. But unfortunately most of the Israelites didn't make it. Their hearts got hardened. So with this in mind he warns the present followers. I believe the warning stands for us too today. Two points emerges from this Scripture.
See to it, brothers, that none of YOU has a sinful.... The question is who is this - YOU? Is it you as an individual or you as a congregation? I think you mean individuals, or in other words you mean me! We should see to it that we don't have a sinful unbelieving heart. The responsibility of guarding our heart is ours.
Above all else, guard your heart, for it is the wellspring of life.
Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous man is powerful and effective.
Since our hearts are deceitful, we must see to it that our hearts are dealt with. Many times we think, or assume, that others are responsible for our hearts. We think, we are like this because of our spouse, or our leadership is not very effective that is why we are not spiritual. We need to take full responsibility for the state of our hearts! Remember, we will be judged individually!
Secondly, but encourage one another ...., not only do we have the responsibility to guard our heart, we need to help or strengthen or give courage to others. It is our duty to help others. We first need to be strong and then need to help those around us to be strong. Many times we are willing to encourage, but we ourselves don't have the courage. We need to get courage from God and give to others.
This Scripture is for all Christian not just for leaders or full time worker. We need to call ourselves and others to guarding our hearts first and then to helping others to be strengthened.