Mishnah 10 - Chapter 2 - Pirkei Avot

They said three things [in derech eretz, in mussar, and in middoth (for in the areas of forbidden-permitted, exempt-liable, they said many things. Or, in these three areas, there was always a "pearl" in their mouths.)] R. Eliezer says: Let the honor of your friend be as dear to you as yours and do not be easily moved to anger. [i.e., when is this possible? When you are not easily moved to anger. (This is one thing; for if you are easily moved to anger, it is impossible not to cheapen your friend's honor.)] And repent one day before your death. [This is the second thing. For since one does not know when he will die, he will repent today lest he die tomorrow.] And warm yourself at the fire of the sages. [This is the third thing.], but be heedful of their coal [not to be lightheaded before them] that you not be burned [i.e., so that you not be punished through them]. For their bite is the bite of a fox, [which is very difficult to heal. For its teeth are small, crooked, and slanted, and the surgeon cuts the flesh with a scalpel to widen the bite], and their sting is the sting of a scorpion, [which is worse than the bite of a snake], and their speech is the hiss of a fiery serpent. [which burns when it hisses. Alternately: The fiery serpent is not to be charmed as other snakes are, as it is written (Psalms 58:6): "He does not heed the voice of the charmers." So, a Torah scholar. If you antagonize him and come to appease him, he is not (easily) appeased], and all of their words are like coals of fire.