If you can cultivate trust in yourself, you can act with integrity and virtue. The mass of your spirit increases.

If the mass of your spirit increases, the push and pull force exerted on you by friends will not materially change you; but may influence your direction or state of motion.

If the force of friendship acts upon you, you will be able to exert the same partner force of friendship upon your friends.

A friend is someone who has the interest of their friends in mind.