Source #1 -- Talmud Bavli Shabbat 31a-b

Reish Lakish said: What is the meaning of the verse “And the faith of your times will be the strength of your salvations, wisdom and knowledge; fear of G-d, that is man’s storehouse” (Yeshaya 33:6)? “Faith” is the order of Zeraim.  “Your times” is the order of Moed.  “Strength” is the order of Nashim. “Salvations” is the order of Nezikin.  Wisdom is the order of Kodshim.  “Knowledge” is the order of Taharoth. Rava said: At the time that man is brought in for judgement, they say to him: Did you conduct your business with integrity and probity?  Did you fix times for Torah study?  Did you involve yourself in procreation?  Did you anticipate and yearn for the redemption?  Did you dissertate in wisdom? Did you understand new things from what you knew?  And even so, if “fear of G-d is his storehouse” then [his judgement is] acceptable. And if not, then it is not.  This is comparable to a man who said to his messenger: “Take up a kur of wheat to the attic.” The messenger went and brought it up. He said to [the messenger]:  “Did you mix in a kav of preservative?”  He said “No.” He said to [the messenger]: “Better that you hadn’t taken it up…Rabba bar Rav Huna said: Any person who has Torah and doesn’t have the fear of Heaven is compared to a treasurer who is given the key to the inner chamber, but is not given the key to the outer entrance.  How can he get in?  Rebbe Yannai proclaimed: It is a pity on those who have no courtyard, but have built a door to the courtyard.

Source #2 -- Talmud Bavli Chullin 94a

We learn: Rabbi Meir says. A person should not prevail upon another to eat at his house knowing that he will refuse. He should not offer presents knowing that the recipient will not receive. He should not open bottles before [a guest] if they are sold to a salesman unless he first informs him. He should not say to him, "Annoint yourself with oil from an empty bottle. If it is for his honor, it is acceptable.

Source #3 -- Shulchan Arukh Choshen Mishpat 228:6

It is forbidden to hurt with words, to mislead people, or to cheat in business transactions
6. It is forbidden to swindle people in business or to deceive them.  For example: If there is a defect in his product, he must inform the purchaser. It is forbidden to sell unkosher meat as if it was kosher meat, even if the purchaser is a non-Jew. One should not give the impression that one is doing something for another, when he really isn’t. For example: He should not urge his friend to eat with him when he knows that the person won’t [accept his invitation].  He should not send gifts when he knows the person won’t take them.  He should not open a fresh barrel of wine, the remainder of which has been sold to a merchant, unless he informs his friend that it wasn’t opened specifically for him.  But if it is the kind of thing the friend should have realized, and he is fooling himself by thinking that it was done to honor him – for example, when a person meets his friend on the street, and the friend thought he had come specially to greet him – it is not necessary to inform him [otherwise].

Source #4 -- Shulchan Arukh Choshen Mishpat 228:9

9. One may not dye a person, nor cattle, nor vessels.  For example, [it is prohibited] to dye the beard of a slave that is being sold, in order to make him appear youthful.  [Nor may one] give bran water to an animal to drink, since it swells and raises the hair, giving the animal an appearance of being fatter…[and it is prohibited] to paint old vessels in order that they should appear new… and to soak meat in water so that it should appear brighter and thicker. (Based on Bava Metzia 60a-b)

Source #5 -- Shulchan Arukh Choshen Mishpat 333:3,5

333: One who hires a worker, and the worker wants to recant from his commitment to work, both before he began as well as afterwards

3: A worker who began working, and then wanted to stop in the middle of the day: He is allowed to do so. Even if he received his wages in advance, and he has no money to return those wages, he can stop working and owe the employer the money that he received.  This is in line with the Torah verse (Vayikra 25:55) "For the Children of Israel are My servants" -- and not servants to [those] servants.

5: When do we allow the worker to recant [from his agreement to do work]?  When there is no irretrievable loss to the employer.  But if the employer will suffer an irretrievable loss -- for example where the worker was hired to take flax out of the soaking pit, or he was hired to bring instruments on his donkey for a funeral or a wedding -- then neither a worker nor a contractor is allowed to recant.  (The work of a maid or a servant is considered to be an irretrievable loss, since it is not appropriate for the head of the household to do their work, and what they were supposed to do cannot be recovered.)  Unless he was a victim of circumstances beyond his control, such as being stricken by illness (whether it was he or his wife or children who became sick) or if he heard that a member of his immediate family died [in which case we will allow the worker to recant]...

[Even when a worker is allowed to recant due to circumstances beyond his control] the employer is not obligated to pay the full wage, but rather only for the proportional amount of work that was actually done.

If the worker recanted without any extenuating circumstances: If the employer could have originally found other workers to do the job, and now he can't, he may hire others in their place [at a higher wage] or trick the original workers [into returning to work].  How does he trick them?  "I promised you one sela -- finish the work and I will pay you two selas."  And when they finish the work, he only has to pay them one sela.  Even if he paid them the additional money, they are required to return it.

Hagah: A worker who does a job for free can recant, even in a situation that causes loss to the owner.

Source #6 -- Shulchan Arukh Choshen Mishpat 337:18-20

337: The laws relating to a worker eating during the time of his employment: From what may he eat, and when can he eat.

18: A worker who eats at a time when he is not supposed to eat; or if he took for himself of the commodity with which he is working, or if he gave it to others, he has transgressed a Torah prohibition.

19: A worker is not permitted to work at night then hire himself out during the day; and he is not allowed to starve or deprive himself in order to give his food to his children, because this undermines the work done for his employer, since he will be too weak to work energetically and diligently.

20: A worker is cautioned against wasting a little time here and a little time there [on the job].  Rather, he is required to be exacting in the amount of time spent working.  For the Rabbis were careful about the fourth blessing of Birkath Hamazon (that a worker should not recite it during his working hours).  And he is required to work with all his energy.  For we see that Yakov [Avinu], the righteous one, said (Breishith 31:6)  "For with all my might I served your father...".  Therefore, he received reward in this world, as it is written "And the man spread out very much" (ibid. 30:43)

Source #7 -- Shulchan Arukh Choshen Mishpat 335:1

335: One who hires a worker without specifying the tasks, or for a specific task.

1: One who hires a [day] worker for a specific task, and the task is completed in the middle of the day: If the employer has other work of a similar nature, or an easier task, he can give it to the worker.  If not, then he pays wages of an idle worker [for the rest of the day].

Hagah: If the employer wants to solicit work from a neighbor to give to his worker [for the rest of the day] he may do so.  There is an opinion that if the employer is willing to increase the wages, the worker can be required to do a more difficult task [than that for which he was hired, for the balance of the day].

If the worker is a manual laborer, who is used to working at very exhausting tasks, such that sitting idle could itself be detrimental to him, then the employer must pay the full wages [even when he has no other work to give him for the rest of the day].  All of the above is limited to a case where the worker wasn't shown the scope of the task before he began working.  But if the employer showed him what needs to be done, and the worker saw that it was not a full day's work, and the worker didn't specify that he was hiring himself out for the entire day, he is not entitled to any payments once the task has been completed. This in line with the principle (in the previous section) which states that any circumstances which are known to both parties requires a stipulation on the part of the worker [if he doesn't want to bear the consequences of the unfolding circumstances].

If a worker was hired for the day with no tasks being specified, the employer can change the task from an easier one to a more difficult one.

(In a case where the employer is responsible to pay wages but has no work to give, it is the court's responsibility to determine whether a specific worker prefers working to sitting idle, in order to determine whether he is entitled to full wages of an idle worker.)

Source #8 -- Shulchan Arukh Choshen Mishpat 339:1-5

339: Paying wages for a person, an animal, or objects, in a timely fashion; and what is considered “timely.”

1. It is a positive commandment to pay the wages of an employee on time, and if he delayed, he has transgressed a prohibition.  This applies equally to the wages of a person, of an animal or of an object.  But for payment of the use of real estate, there are those who say it is not a transgression.

2. Anyone who holds back the wages of an employee is comparable to one who takes his life, and he trangresses five prohibitions and one positive commandment.

3. What is considered “on time”?  For a day worker, wages can be given throughout the night.  If he didn’t pay them, then in the morning, the employer has transgressed “Do not hold wages overnight” (Vayikra 19:13).  For a night worker, the time is the entire day. If he fails to pay (during the day), then on the (following) evening he violates “And on its day, you shall give his wages” (Devarim 29:15).

4. An employee hired by the hour: If the employment is completed in the day, he can be paid anytime during the day.  If it is completed at night, he can be paid during that night.

5. An employee by the week, by the month, by the year…if the period concludes during the day, he collects anytime during that day.  If it concludes at night, he collects anytime during that night.

Source #9 -- Talmud Bavli Bava Metzia 83a

Porters hired by Rabbah bar bar Chanan broke a barrel of wine (that they were transporting, due to their negligence).  He confiscated their shirts (as collateral for payment of the broken barrel). They came to Rav (to adjudicate the case). [Rav] said to him: Give them back their shirts (without receiving the payment).  He said to [Rav]: Is this the [correct] law?  [Rav] said to him: Yes, “In order that you should walk on the path of the good” (Mishlei 2:20).  He gave them their shirts.  They said to him: We are poor people, we have worked all day, we are hungry, and we have nothing.  [Rav] said to him: Pay them their wages.  He responded to [Rav]: Is this the [correct] law? [Rav] said to him: Yes, “and keep the paths of the righteous” (ibid.).

Source #10 -- Talmud Bavli Kiddushin 59a

Rav Giddel was negotiating [to purchase] a field.  Rebbe Abba went and bought it.  Rav Giddel went and complained to Rebbe Zeirah.  Rebbe Zeirah went and complained to Rav Yitzchak Nafchah. He said to him: “Wait until he comes up to visit us for the festival.”  When [Rebbe Abba] went up, [Rav Yitzchak Nafchah] found him and said to him: “A poor person who is examining a cake, and someone comes and takes it from him. What [is the law]?” He said to him: “He is called an evil person.”  “So why did you do so?”  He said to him “I didn’t know.”  “So now you should return it to him.” [Rebbe Abba] said to him: “I will not sell it, because it is my first piece of land, and it is not a good omen.  If he wants it as a present, he can take it.”  Rav Giddel didn’t take possesion of the land, for it is written “One who hates presents will live” (Mishlei 15:27).  Rebbe Abba didn’t take possession of the land, because Rav Giddel had been negotiationg for it.  Neither this one nor that one took possession, and it was called “The land of the Rabbis” (available freely to their students).