This is great stuff by Edwards. In the 11th lecture of Charity and Its Fruit, Edwards convincingly declares that men’s practice will be according to their convictions. That is, if a man truly believes something, he will act on it and if he does not act on it, it seems that he is not really and entirely convinced of that truth.
Nowhere is this more true than in man’s dealings with the gospel. Gospel-truth is efficacious truth; if you believe it sincerely, your life is changed and this results in a change in the manner in which you live your life.
If a man hears important news that concerns himself, and we do not see that he alters at all for it in his practice, we at once conclude that he does not give heed to it as true; for we know the nature of man is such, that he will govern his actions by what he believes and is convinced of. And so if men are really convinced of the truth of the things they are told in the gospel, about an eternal world, and the everlasting salvation that Christ has purchased for all that will accept it, it will influence their practice. They will regulate their behaviour according to such a belief, and will act in such a manner as will tend to their obtaining this eternal salvation. If men are convinced of the certain truth of the promises of the gospel, which promise eternal riches, and honours, and pleasures, and if they really believe that those are immensely more valuable than all the riches, and honours, and pleasures of the world, they will, for these, forsake the things of the world, and, if need be, sell all and follow Christ. If they are fully convinced of the truth of the promise, that Christ will indeed bestow all these things upon his people, and if all this appears real to them, it will have influence on their practice, and it will induce them to live accordingly. Their practice will be according to their convictions.