"12 Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God. 13 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. 14 For we have come to share in Christ, if indeed we hold our original confidence firm to the end. 15 As it is said,
“Today, if you hear his voice,
do not harden your hearts as in the rebellion.”
Hebrews 3:12-15
These words crystallise the real nature of the problem and the warning - an evil heart of unbelief. This was the root of the matter so far as the Israelites were concerned - not amiable weakness or unfortunate failing, but hearts infected and corrupted and hardened by the deceitfulness of sin. This is to call an ugly thing by its proper name. Unbelief is not an affliction to be struggled with, but a sin to be confessed and forsaken, and it is part of the deceptive power inherent in sin that we should so often fail to realise this. How easy it is to be deceived in the spiritual life, especially when there is such a subtle fifth-column within us aiding and abetting every outward temptation to yield to the deception! A constant watch needs to be kept against the snares and wiles of Satan. To help us in this the Apostle adds, 'Exhort one another daily'. But there is exhortation and exhortation, and we scarcely think he would hold any brief for the kind of Christian who conceives it as his duty to go around putting everybody right. It is bad psychology as well as unhelpful spiritually to be constantly censorious and self-righteously critical in one's attitude to others. It is paradoxical but true that those who are most fitted, by reason of their spiritual maturity and discernment, to admonish and exhort their fellow believers, are less inclined and more restrained than those who are not. This is why, when they do exercise this spiritual discipline, their words are worth heeding. Nor must we forget that the inspiration and example of a faithful and consistent walk is often a much more eloquent exhortation than many words could ever be.