Stephen Charnock (Works, Vol. 4, pp. 488-489):
'The heart of man is deceitful,’ Jer. 17:9. It is the great impostor and cheat of the world, the antichrist within us, the deceiver of our souls, as the great antichrist is called the deceiver of the nations. How apt are we to take upon trust what our heart first speaks! James and John could tell Christ that they were able to drink of his cup, and no question they meant as they spake, Mat. 20:22; but had it come to a trial, they would not have endured to sip of it; and the issue manifested it: they turned their backs upon him, as well as the other disciples. The Israelites, had they tried themselves by their present resolution, Deut. 5:27, ‘All that the Lord our God shall speak unto thee we will hear and do it,’ might have subscribed themselves as pious as any in the world; they spake no other than they meant. But God had a further inspection into them than they had into themselves: ver. 9, ‘Oh that there were such a heart in them that they would fear me, and keep my commandments always!’ Natural conscience is often silenced by a pretence and a show, and a man is naturally apt to make his own corrupt judgment, sometimes also his passion, the standard of good and evil, and not only to frame grace according to his own affections, but a god also: Ps. 50:21, ‘Thou thoughtest that I was altogether such an one as thyself.’ The apostle intimates it in that signal mark of caution, when he presseth a truth to which natural conscience will subscribe, that ‘neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor covetous, nor drunkards, shall inherit the kingdom of God;’ 1 Cor. 5:9, ‘Be not deceived,’ saith he: even in these things men may deceive themselves with false hopes, much more in moral righteousness. Many boast themselves rich in spirituals when they are really poor; so did Laodicea think herself rich when God gave her another inventory of her estate, that she was ‘poor and miserable, and blind and naked,’ Rev. 3:17. There is too much resting in the world upon outward privileges,* and often beggars conceit themselves princes because they dream of sceptres. How many extend their hopes as far as their wishes, and these as far as a fond fancy and imagination!