The rabbis consider the secrets of the higher levels and wonder how it is possible to reveal them, because they seem so mysterious. They are told not to try to reveal them, for it is not time to bring the higher wisdom down to the lower levels.
398. One day, Rabbi Yesa asked about the following. He said: A true egg that laid the bird who dwells in fire breaks up into four sides. Two rise from them, one is lowered and one squats by the great sea. Rabbi Aba said: Are you making before Rabbi Shimon the holy into profane, about whom it is written, "With him I speak mouth to mouth" (Bemidbar 12:8)? Rabbi Shimon said to him: BEFORE the time of the egg to split, you will depart from this world. This happened in the gathering of Rabbi Shimon.
399. We have learned that during the days of Rabbi Shimon a person would say to his friend: Open your mouth and let your words shine forth. After the demise of Rabbi Shimon, they would say, "Do not let your mouth cause your flesh to sin" (Kohelet 5:5), MEANING DO NOT REVEAL SECRETS.