“I would advise you not to expect too much happiness, even from the fulfillment of all your wishes. The moment you have distinguished yourself you become an object of envy and malice; men whom you believed to be lovers of knowledge you will then find to be lovers only of fame, and haters of all knowledge that has not come from themselves. You will find that a life of science has in it no superiority to any other, unless it is pursued from a higher principle than the mere ambition of notoriety, and that demagogue or a philosopher differ only in the objects of their selfishness. As you will now have experienced how unsatisfying even the pursuit of knowledge is when insulated from higher objects, I hope, if you have not been fortunate enough to begin the study earlier, that you will devote yourself to the most extraordinary of all subjects, one which infinitely surpasses the mechanism of the heavens or the chemistry of the material world, the revelation of your duty and the destiny of man as contained in The Bible — a book which occupied the best hours of the manhood of Newton, of Locke, and of Euler.”

In a 1830 letter to James David Forbes, as found in Life and letters of James David Forbes, p. 40.