Bava Batra

Why have you acted thus [i.e. killed only the males]? He replied: Because it is written, Thou shalt blot out the males [zekar] of Amalek.  Said David: But we read, the remembrance [zeker]  of Amalek? He replied: I was taught to read zekar.  He [Joab] then went to his teacher and asked: How didst thou teach me to read? He replied: Zeker. Thereupon he drew his sword and threatened to kill him. Why do you do this? asked the other. He replied: Because it is written, Cursed be he that doeth the work of the Lord negligently.  He said to him: Be satisfied that I am cursed.  To which Joab rejoined: [It also says]. Cursed be he that keepeth back his sword from blood.  According to one report he killed him; according to another, he did not kill him. Raba further said: A teacher of young children, a vine-dresser, a [ritual] slaughterer, a blood-letter, and a town scribe are all liable to be dismissed immediately  [if inefficient]. The general principle is that anyone whose mistakes cannot be rectified  is liable to be dismissed immediately [if he makes one]. R. Huna said: If a resident of an alley sets up a handmill and another resident of the alley wants to set up one next to him, the first has the right to stop him, because he can say to him, 'You are interfering with my livelihood.' May we say that this view is supported by the following: 'Fishing nets must be kept away from [the hiding-place of] a fish [which has been spotted by another fisherman] the full length of the fish's swim.' And how much is this? Rabbah son of R. Huna says: A parasang?' — Fishes are different, because they look about [for food]. Said Rabina to Raba: May we say that R. Huna adopts the same principle  as R. Judah? For we have learnt: R. Judah says that a shopkeeper should not give presents of parched corn and nuts to children, because he thus entices then, to come back to him. The Sages, however, allow this! — You may even say that he is in agreement with the Rabbis  also. For the ground on which the Rabbis allowed the shopkeeper to do this was because he can say to his rival, Just as I make presents of nuts so you can make presents of almonds;  but in this case they would agree that the first man can say to the other. 'You are interfering with my livelihood.' An objection was raised [against Rab Huna's ruling from the following:] 'A man may open a shop next to another man's shop or a bath next to another man's bath, and the latter cannot object. because he can say to him, I do what I like in my property and you do what you like in yours?' — On this point there is a difference of opinion among Tannaim, as appears from the following Baraitha: 'The residents of an alley can prevent one another from bringing in  a tailor or a tanner or a teacher or any other craftsman,  but one cannot prevent another  [from setting up in opposition].' Rabban Simeon b. Gamaliel, however, says that one may prevent another. R. Huna the son of R. Joshua said: It is quite clear to me that the resident of one town can prevent the resident of another town [from setting up in opposition in his town] not, however, if he pays taxes to that town — and that the resident of an alley cannot prevent another resident of the same alley [from setting up in opposition in his alley].  R. Huna the son of R. Joshua then raised the question: Can the resident of one alley prevent the resident of another [from competing with him]?  — This must stand over. R. Joseph said: R. Huna agrees that a teacher cannot prevent [another teacher from setting up in the same alley], for the reason mentioned,