Hebrews 3:13 - Matthew Poole's English Annotations on the Holy Bible

Ver. 13,14 But exhort one another daily, while it is called To-day: the means to avoid the former evil is, to exhort; which, as a private duty, is an earnest, frequent calling on, stirring up, or persuading, encouraging to perseverance in the Christian religion, and to put away all heart evil, especially unbelief, which traineth to apostacy; to which are subservient God's precepts, promises, threatenings suitably applied by them. And this is not only privately, but especially publicly, by the regular ministration of the word and ordinances to the whole society of Christians, as they are personally obliged to it, being members one of another, 1 Corinthians 12:25,27. And this they are to do instantly, for no man is sure what may be on the morrow, he being but a days-man, living, and supplied, as working by the day: Sufficient to the day is the duty as well as the evil in it, Matthew 6:11,34. Whilst then the day of grace and repentance lasts, in which God calls and entreats, and will hear and help, the opportune time of exhorting, the very instant wherein God expecteth it, Hebrews 3:7 Psalms 95:7. And every one, as thus to look to another, must begin with himself, lest any miscarry; charity, especially as to this, should begin in every Christian at home. Lest any of you be hardened through the deceitfulness of sin; lest themselves or others refuse the gospel tendered, or reject and apostatize from it after professing it, so as to become not only obstinate, but rebellious, by unbelief, and an habitual hardened heart; so as the sinful, natural habit of our soul, James 1:12,15, so horribly vile in itself, that were it not masked nature would abhor it, might be drawn forth by the false colours, as the devil blinds sin with, to delude the understanding, and to catch and insnare the malignant will, that it swallows it more and more, to the hardening of the heart; that Divine promises, threatenings, nor admonitions, can make any impression; it being unmoved under the application of all these, disregards the Christian faith, and hath its issue in a total apostacy, Jeremiah 17:9 Ephesians 4:22 1 Timothy 1:19.