To prick the sides of my intent, but only
Vaulting ambition which o'erleaps itself,
And falls on the other";
meaning that he had no motive whatever for killing Duncan except the ambition to occupy his throne. Ambition destroyed him. Frederick the Great bound himself to befriend and support the young ruler of Austria, yet he violated his oath, robbed his ally, and plunged Europe into a long and desolating war. To quote his own words: "Ambition, interest, the desire of making people talk about me, carried the day, and I decided for war." He sacrificed his own soul for the sake of the glory arising out of victorious war.
The danger of Ambition to young men is that it leads to discontent with their present lot in life. Many a young man has been utterly ruined by giving way to discontent because of Ambition. A young man in a bank, filled with Ambition, wishes to improve his position. His salary is small, and he feels cramped. He begins to speculate through brokers, paying a little cash down. Perhaps he is successful at first. Then he hears of some railway shares that are going up in price every day. If he can only get some money to buy he can repay it in a week, and make a great profit for himself. He takes the bank's money. He does this several times, until at last the crash comes, as it always does, and the young man is sent to spend some of the best years of his life in gaol. Ambition has destroyed his reputation, and has cost him his liberty and his friends.
To excel in his present calling, is a lawful Ambition for a young man, leaving it to the future, to his reputation, and to God, to lift him higher. How much wiser and happier Macbeth would have been if he had kept to his first resolution:
"If chance will have me king, why, chance may crown me."
It is quite possible for Ambition and Contentment to go together, and to produce the very greatest results in the long run. This was the ambition of General Gordon, that he might excel others as a soldier, and yet be content with a position humble as men count such things. He refused repeated offers of money from the Emperor of China. He accepted the Peacock Feather and Yellow Jacket to give pleasure to his mother, and to enable him to exert the necessary influence upon the Chinese in settling the country after the horrors of war. This was the kind of Ambition held by Livingstone, by Palissy the potter, and, above all men in modern times, by Faraday. When Faraday made known some of his discoveries, he was offered large sums to make experiments for merchants, and he might soon have become very rich, but it would have taken all his time. He refused; he remained poor; he gave himself up to scientific research, and he made the name of England great in the scientific world, as it had never been before.
The highest Ambition a man can have is to be able to make a sacrifice of his inclinations, and to give himself up to some noble work for the good of mankind, without any thought of profit or pride, or place or power, or any other form of selfishness.