What would be an essay, based on The Three Musketeers, on the idea that sometimes a friendship is born out of conflict?

The idea that friendship grows out of conflict can be seen in two primary ways in The Three Musketeers. First, and more generally, the musketeers themselves are brought together in a common cause. They form an elite squad of fighting men who support the crown and oppose Cardinal Richelieu. With their motto of “all for one, one for all,” they exemplify unity and loyalty of friendship that comes from supporting a cause and those who share their values.
Second, d’Artagnan’s entry into the musketeers stems from an initial conflict. The young man is so anxious to prove himself and to join their ranks that when they first meet, he sets himself against them. Convinced of his own worth and sensitive to any criticism, he challenges Athos, Porthos, and Aramis to duels. When the cardinals’ guards arrive, however, he quickly sets aside this contest, and they join forces to fight them off. This incident leads to his friendship with the other three.