Midrash su Ecclesiaste 10:9

“One who transports stones will be saddened by them; and one who splits wood will benefit from it” (Ecclesiastes 10:9).
“One who transports stones will be saddened by them” – one who transports himself from his studies will ultimately be sorry. He will seek a matter but will not find it.⁴⁸He will seek to recall some detail of his Torah study but will not remember it.
“And one who splits wood will benefit [yisakhen] from it.” As long as he toils in it, he will benefit from it, just as you say: “She will be an attendant [sokhenet] for him” (I Kings 1:2).
Another matter: “One who transports stones” from place to place “will be saddened by them”; “and one who splits wood will benefit from it.”⁴⁹Previously the midrash interpreted the phrase “one who transports stones” to refer to one who removes himself from Torah study, as stones are an allusion to the tablets given at Sinai. Now the midrash interprets the verse literally as referring to one who moves stones from place to place. Unscrupulous individuals might remove stones from their fields to the public domain, but ultimately it is they who will stumble (Midrash HaMevo’ar). Rabbi Meyashya said: In reward for the two logs that Abraham chopped on Mount Moriah, he was privileged to have the sea split for his descendants into twelve strips.

R. Zera in the name of Rab said: "What is the meaning of (Prov. 15, 15) All the days of the afflicted are evil? This refers to the masters of Gemara [because they must find out how to decide the laws from the Mishnayoth, which always need an explanation]. "But he that is of a cheerful heart," etc., refers to the one who is a master in Mishnah. Rabba, however, maintains the reverse. And this is what R. Mesharshia said in the name of Raba: "What is the meaning of the passage (Eccl. 109) He that moves stones will be hurt through them, he that cleaveth wood will be endangered thereby, i.e. he that moves stones will be hurt by them, refers to the masters of the Mishnah; he that cleaveth wood will be endangered thereby, refers to the masters of Gemara, because they do not always succeed in finding out the correct decisions." R. Chanina said: "All the days of the afflicted, etc., refers to one who has a bad wife, but he who is of a cheerful heart, etc., refers to one who has a good wife." R. Janai said: "And the days of the afflicted, etc., refers to one who is fastidious; and he that is of a cheerful heart, etc., refers to one who has a good physical constitution." R. Jochanan said: "All the days of the afflicted are evil. refers to one whose nature is merciful, and who takes to heart everything which happens to his fellow-men; but he that is of a cheerful heart, etc., refers to him who is merciless." R. J. Joshua b. Levi said: "All this, etc., refers to one who is pendantic; but he, etc., refers to him whose mind is worldly."

(Exodus 14:26) "And the L rd said to Moses: Stretch forth your hand over the sea": It will not stand against you and it will not deviate from your command. "and the waters will turn back upon Egypt, upon its chariots, and upon its riders": The "wheel" will turn back upon them. For with the counsel that they thought to destroy Israel, I will destroy them. They thought to destroy Israel by water, and it is by water that I will exact punishment of them, viz. (Psalms 7:16) "He has dug a pit and he has deepened it, and he will fill in the pit he has wrought", (Koheleth 105:8-10) "He who digs a hole will fall in it; he who breaches a fence will be bitten by a snake. He who quarries stones will be saddened by them; he who splits timbers will be imperiled by them", (Mishlei 26:27) "The digger of a pit will fall in it, etc." And thus Solomon says (Ibid. 12:14) "From the fruit of a man's mouth, he will be sated with good, and the payment of a man's hands will revert to him." And thus, Isaiah the prophet (Isaiah 59:18) "As with reward (for good), so will He return wrath to His enemies, payment to His foes — to (distant) isles will He bring retribution." And it is written (Ibid. 65:7) "And I will measure out (retribution for) their deeds, etc." And thus did Jeremiah the prophet say (Jeremiah 32:19) "Wondrous in counsel and mighty in deed, whose eyes are open to all the ways of the sons of man, to give each man according to his ways and according to the fruit of his deeds." And thus is it written (Ibid. 50) "Summon many against Bavel, all who draw the bow. Encamp against her roundabout. Let there be no escape for her. Repay her according to her deeds. According to all that she has done, do to her. For she has acted insultingly against the L rd, against the Holy One of Israel." And thus did Yithro say to Moses (Exodus 18:11) "Now I know that greater is the L rd than all the gods." I recognized Him in the past, and now, even more so, His name having been magnified in the world. (Ibid.) "For (they were destroyed) by the (very) thing (water) whereby they devised evil against them."