Midrash su Ecclesiaste 7:3

R. Juda the son of R. Samuel b. Shilath in the name of Rab said: "The sages wanted to suppress (declare uncanonical) the book of Ecclesiastes because its words are contradictory; but why did they not suppress it? Because it begins and ends with words concerning the Torah. It begins with the words concerning the Torah, for it is written (Ecc. 1, 3.) What profit hath a man of all his toil which he toileth under the sun? Whereupon the school of Janai said, for a thing which [was created] under the sun he hath no profit, but for a thing which is beyond the sun (before creation) he will have profit. It ends with words concerning the Torah, for it is written (Ib. 12, 13.) The end of the matter is, let us hear the whole; fear God and keep His commandments; for this is the whole (duty of) man. What is meant by, this is the whole man? R. Eliezer said: "It means the whole world was created for the sake of him (who fears God)." R. Abba b. Cahana said: "This [fear of God] is equal in importance to the whole world put together." Simon b. Azai and, according to others, Simon b. Zoma, said: "The whole world would not have been created if not for the purpose of providing him (who fears God) with company." And what are the words which contradict each other? It is written (Ecc. 7, 3.) Better is vexation than laughing; and again it is written (Ib. 2, 2.) Of laughter I said, it maketh one praiseworthy; and it is also written (Ib. 8, 15.) Therefore do I praise joy: and again (Ib. 2, 2.) And of joy what doth this do? There is no contradiction; Better is vexation than laughing, means that, the vexation which the Holy One, praised be He! causeth unto the righteous in this world is better than the smile which the Holy One, praised be He! causeth unto the wicked in this world; Of laughter I said, it maketh one praiseworthy, speaks of the smile with which the Holy One, praised be He! will gladden the righteous in the world to come. Therefore do I praise joyfulness, refers to a rejoicing which is caused by a meritorious deed; And of joy what doth this do? alludes to rejoicing which is not the cause of a meritorious deed. We infer from this that Shechinah rests not upon a mood of indolence, nor a mood of grief, nor a mood of laughter, nor a mood of levity, nor a mood of jesting, nor a mood of idle talk, but upon a mood of rejoicing caused by the performance of a meritorious deed; as it is said (II Kings 3, 15.) But now bring me a musician, etc, R. Juda said: "The same should be applied to the study of the Halacha (Laws)." Raba said: "The same is to be applied to a good dream." Is it so? [that Halacha should be preceded by a cheerful thing] . Behold, R. Gidel in the name of Rab said: "Any disciple who sits before his teacher without dropping bitterness from his lips [on account of respect] will be burnt, for it is said (Songs 5, 13.) His lips like lillies, dropping with fluid myrrh. Do not read Mor (fluid myrrh), but read it Mar (bitterness. Do not read Shoshanim (lilies) but read it Sheshonin (who study); [hence we see that a disciple must act with deep respect, and not in a frivolous mood]. This is not difficult to explain: the former refers to the teacher and the latter refers to the disciple; and if you wish you may say both refer to the teacher; and even then there is no contradiction; for the former refers to the time before beginning [the lecture] and the latter refers to the time after the lecture has begun. Just as Rabba did before he began [his lecture] before the Rabbis. He said something humorous which caused the Rabbis to be cheerful, and he then sat down with deep respect to expound the Halacha.