מַסִּ֣יעַ אֲבָנִ֔ים יֵעָצֵ֖ב בָּהֶ֑ם בּוֹקֵ֥עַ עֵצִ֖ים יִסָּ֥כֶן בָּֽם׃
돌을 떠내는 자는 그로 인하여 상할 것이요 나무를 쪼개는 자는 그로 인하여 위험을 당하리라
Rashi
To debate over a matter from which he derives no benefit Heb. יסכון. To debate over a matter from which he will derive no benefit, like (I Kings 1:2), “and she shall be to him a warmer (סכנת),” and like (Ecc. 10:9), “is warmed (יסכן) by it,” i.e., he will derive benefit from it.
Rabbeinu Bahya
וירא משם את קצה העם, “He could see from there a portion of the people.” He could not see all of them. The reason was that their encampment extended in all four directions of the globe. Balak was very eager to lead Bileam to heights from which he could see them and focus his eye on them as he believed Bileam’s power to curse to repose in his evil eye. The eye, or the manner in which it sees, reflects the inner soul. Our sages in Baba Kama 117 comment on this: (in connection with a story involving Rabbi Yochanan and Rabbi Kahane where a stare from Rabbi Yochanan who mistakenly thought that Rabbi Kahane had made fun of him killed Rabbi Kahane). Rabbi Yochanan had used his eyes as conveying a curse. The reason that such stares from great Torah scholars can have such lethal effect is that these scholars cannot stand being deflected from thoughts of Torah even momentarily. When they encounter persons who cause them to be deflected from Torah thoughts they resent this strongly and when they look at the person causing this their look reflects their anger. They view the person having caused them to become deflected from pure Torah thoughts as if guilty of heresy, deserving to be cursed. This may be the meaning of Kohelet 10,9 ”He who splits logs, עצים, will be endangered by them.” If someone becomes the cause of the עץ החיים, i.e. Torah, to be “split,” to be interrupted, he endangers his life by doing so.
It is true, of course, that we find many times that the words or stares of great Torah scholars, pious individuals, do not appear to have any harmful effects at all; the matter is something which is subject to the individual. The makeup of the personality of the individual scholar determines if his stare can be potentially lethal. One requires this particular gift in addition to great Torah knowledge in order for one’s stare prompted by one’s anger to have such harmful effects as reported in the Talmud of certain outstanding personalities.
It is true, of course, that we find many times that the words or stares of great Torah scholars, pious individuals, do not appear to have any harmful effects at all; the matter is something which is subject to the individual. The makeup of the personality of the individual scholar determines if his stare can be potentially lethal. One requires this particular gift in addition to great Torah knowledge in order for one’s stare prompted by one’s anger to have such harmful effects as reported in the Talmud of certain outstanding personalities.