Suppose that a man were to come along carrying a burning grass torch and saying, 'With this burning grass torch I will heat up the river Ganges and make it boil.' Now, what do you think — would he, with that burning grass torch, heat up the river Ganges and make it boil?"
"No, lord. Why is that? Because the river Ganges is deep & enormous. It's not easy to heat it up and make it boil with a burning grass torch. The man would reap only a share of weariness & disappointment."
"In the same way, monks, there are these five aspects of speech by which others may address you: timely or untimely, true or false, affectionate or harsh, beneficial or non beneficial, with a mind of good-will or with inner hate. Others may address you in a timely way or an untimely way. They may address you with what is true or what is false. They may address you in an affectionate way or a harsh way. They may address you in a beneficial way or an non beneficial way. They may address you with a mind of good-will or with inner hate. In any event, you should train yourselves: 'Our minds will be unaffected and we will say no evil words. We will remain sympathetic to that person's welfare, with a mind of good will, and with no inner hate. We will keep pervading him with an awareness imbued with good will and, beginning with him, we will keep pervading the all-encompassing world with an awareness imbued with good will equal to the river Ganges — abundant, expansive, immeasurable, free from hostility, free from ill will.' That's how you should train yourselves.