Hebrews 3:12-14 says, "Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God. But exhort one another every day, as long as it is called 'today,' that none of you may be hardened by the deceitfulness of sin. For we have come to share in Christ, if indeed we hold our original confidence firm to the end."
Situation: The people are tempted to "fall away from the living God".
Response: Exhort those who are tempted.
But, what does "exhort" mean? Does it mean to keep someone in obsessive self-examination? Does it mean to beat yourselves up because you don't have enough faith?
Exhort means to "summon, encourage, comfort, implore". The root word has been used by kings to call a council to meet. It has also been used to address someone by name. This particular word is used for "encouraging" and "to cheer someone on".
In other words, when we see someone who is battling unbelief, the answer is not to beat them up but to "cheer them on". Not in a trivial way that makes light of a situation but in a way that encourages them that God is at work. Yes, we must repent of unbelief. But, what is the motivation to grow in faith? It is by gospel encouragement.
Exhort People To What?
First, the text calls us to exhort people in the sufficiency of Christ. This is what the entire letter of Hebrews is about. Jesus is the radiance of the glory of God (1:3), the sufficient priest who made atonement and sits at the right hand of the Majesty on high (1:3), greater than the angels (1:5-14), the founder of our salvation (2:10), true Man (2:14-18), the greater Moses (3:1-6). The letter goes on to say that Jesus is the true Sabbath rest (4:1-10), the Great High Priest who can sympathize with us (4:14-5:10), a priest like Melchizedek (7:1-28), Priest of a better Covenant (8:1-13), the True Temple (9:1-28), the ultimate Sacrifice (10:1-18), the sustainer of our faith (11:1-40), the Perfecter of our Faith (12:1-2).
Notice how much of the focus is on the majesty of Christ. It is overwhelmingly clear that if we're going to encourage someone's faith that we do so by showing them the majesty of Jesus Christ.
Second, we exhort people to understand the deceitfulness of sin. We encourage them that the way of Christ is better. Sin won't satisfy them in the end. Turning away from Christ to something else won't grant assurance. Their conscience won't be able to find rest. We do have to expose the dangers of the deceitful nature of sin. But, we do so all the while showing them Christ.
Third, we exhort people that we actually "share in Christ". We come to actually partake of Christ through union with Him. It is the same word used when we partake of Christ in the Lord's Supper. We share in His resurrected and ascended life. And this new life is a life that has overcome death. Chrysostom says, "What is it to ‘share in Christ’? It is when he and we are made one; he the head, we the body, co-heirs and incorporated in him. We are one body with him.”
What Do We Learn Overall?
As John Owen says, "All exhortation should be only through consoling words and ways...So to encourage is to persuade people with humble, comforting words, consoling them so that they may be comforted." For each individual person, based on who they are and what they're going through, we seek profitable ways to encourage them in Christ. We seek to show them the sufficiency of Christ and how He is able to meet someone in their sins and sufferings. As the Vine is feeding the branches, so Christ is feeding and nourishing us.