The Gemara in Sanhedrin 5a relates that when Raba b. Chana and Rav went to Bavel, R. Chiya asked Rebbe on their behalf for permission to rule and to judge. The Gemara (5b) asks, if they were learned, why did they need permission? The Gemara answers that in the times of Rebbe there were incidents in which a talmid's ruling had been misunderstood by the people, so the Sages decreed of that a talmid should not rule without first receiving permission from his rav. The Gemara then relates the story of Rav Tanchum who inadvertently issued a ruling in the proximity of his rav. Later, the Gemara quotes a braita that a talmid should not rule in the locale of his rav unless he was three parsaot (7-8 miles) away from him, like the size of the camp of Israel in the wilderness.

At first glance, there seems to be a problem with this sugya. It would appear that the need for a talmid to ask permission of his rav was because of the incident in Rebbe's time, yet the sugya concludes with the issue of talmid ruling in the locale of his rav. Thus, did Rav Tanchum have permission or not? If he did, he should have been permitted to rule even within three parsaot; if not, he should have been forbidden anyway because of Sages' decree! Clearly there are two laws:

A talmid should not rule in the locale of his rav because of the honor of his teacher (kvod rabo). This is learned from Moshe Rabbeinu and the Israelite camp, and is restricted to three parsaot. Beyond this, the rav is not available, and there is no slight to his honor.

The talmid requires confirmation that he is fit to rule, i.e., that his is knowledgable and can convey the halacha clearly. This law is not linked to the kvod harav. The parameters of kvod harav learned from Moshe are found in Eruvin 63a. Rava summarizes the halacha as follows: "In [the rav's] presence it is forbidden [for the talmid to rule], and he is deserving of death; not in his presence it is forbidden, but he is not deserving of death." The Gemara there further distinguishes between a regular talmid and a "talmid chaver" (a talmid who has achieved a sufficient level that the rebbe can give and take with him). Tosfot concludes, based on this sugya, that a regular talmid ("talmid gamur") is not allowed to rule even beyond three parsaot, but does not deserve death unless he rules within three parsaot. A talmid chaver is one level better -- he is permitted beyond three parsaot, and within three is still not allowed, but is not deserving of death.

The Rambam writes in Hil. Talmud Torah 5:2-3 as follows:

A person may never rule in the presence of his rav, and anyone who does so is deserving of death.If there was between him and his rav 12 mil (=three parsaot) and a person asked him a matter of halacha he may answer ... But to establish himself for ruling, and to sit and rule to all that ask, even if he is in one end of the world and his rav is in the other end of the world, he may not rule until his rav dies, unless he received permission from his rav. The Rambam introduces a new distinction between one who rules on an occasional basis and one who establishes himself to rule. Where did he find a basis for this distinction?

From the Rishonim is seems that there is a contradiction between the sugyot. The implication of the sugya in Sanhedrin is that beyond three parsaot a talmid is permitted to rule, whereas in Eruvin it seems that even beyond three parsaot he is not allowed to rule! Tosfot answered by distinguishing between a talmid gamur and a talmid chaver. (Alternatively, Tosfot in Sanhedrin explains that Eruvin is dealing with a case where he did not receive permission). The Rambam apparently resolved this contradiction by distinguishing between an occasional ruling and an established forum.

There is a strong question against Tosfot. If a talmid gamur is not allowed to rule even beyond three parsaot of his rav, as implied in Eruvin, why does the Gemara Sanhedrin ask, "If he is learned why does he need permission?" A talmid gamur is not allowed even beyond three, and relative to Rebbe, Rav and Raba b. Chana were talmidim! Furthermore, why must the Gemara answer because of the incident, it is because without permission they are not allowed!

This is a question also against the Rambam, since they were going down to Bavel to establish a Yeshiva and rule on a regular basis, so how could the Gemara ask why permission is necessary? It must be that Rav and R. Chanina went without intentions to rule on regular basis. And thus, when the Gemara answers because of Rebbe's decree, this implies that the decree is even for an occasional ruling beyond three parsaot. Then why did the Rambam omit the halacha of our sugya that even to rule occasionally is not allowed without confirmation because of the decreee? (Aruch Hashulchan)

The Shulchan Aruch quotes the Rambam in Yoreh De'ah 242:5. The Rama adds that a talmid chaver is allowed to rule even within three parsaot. What is his basis that this is true even according to the Rambam (who answered the contradiction in the sugyot differently than Tosfot)? Furthermore, even Tosfot only distinguished between a talmid gamur and talmid chaver beyond three parsaot, so how does the Rama write that a talmid chaver may rule even within three parsaot?

There is a third opinion, that of the Rashba. He rejects Tosfot's position that even beyond three parsaot a talmid is not allowed to rule due to his rav's honor (unless he is a talmid chaver). Firstly, if Tosfot were correct, then what is our Gemara's question? Furthermore, the Gemara explicitly states that a talmid may not rule unless he is a distance of three parsaot. The implication is that beyond three parsaot is allowed, and since it doesn't stipulate talmid chaver, it sounds like anyone may do so. Furthermore, the source of this halacha is derivcd from Moshe, and everyone is like a regular talmid relative to Moshe!

Therefore, the Rashba concludes that kvod rabo is only within three parsaot, as learned from Moshe. Rava's statement in Eruvin, "Not in his presence is prohibited, but not deserving of death," is within three parsaot, and the distinction is between in his presence literally and not in his immediate presence. That is why the Gemara in Sanhedrin asked, why did Raba b. Chana and Rav need permission? The answer is that although kvod rabo is no longer relevant, there is a new reason to ask permission, because of the decree in the times of Rebbe. But then how could the braita say that beyond three parsaot a talmid is allowed to rule? This braita is talking from the perspective of kvod rabo alone, but in fact he still needs authorization in order to rule. The significance of three parsaot, though, is if gets permission from another rav, it will suffice to fulfill the decree.

We can now suggest a new understanding of the Rambam. The Rambam opinion is similar to the Rashba's principle. Beyond three parsaot is not a slight to the rav's honor even if one establishes himself for horaah. Indeed, Rav went to establish a permanent Yeshiva, and still the Gemara asked why did he need permission (since he was going beyond three parsaot)? If so, the answer that a talmid needs permission because of Rebbe's decree is also limited to one who rules on a regular basis. This is logical, since the concern that the posek will accidentally mislead the people is primarily a concern for one who will rule with authority on a regular manner. Thus, Raba's statement that beyond three is not allowed is because of Rebbe's decree, and not because of the rav's honor.

The Gra (Y.D. 242:[8]) seems to indicate this way. On the words of the Shulchan Aruch, "If he is twelve mil distant from his rav," the Gra writes that the Ramam interpreted the sugya in Sanhedrin as referring to one who wants to rule in a permanent manner. About this the Sages decreed that a talmid must receive permission. On an occasional basis it is only prohibited within three parsaot.

Thus, there is no contradiction between the sugyot. As far as kvod rabo there is no distinction between ruling occasionally and on a regular basis. In any case, beyond three parsaot there is no problem of kavod, and in the rav's presence (i.e., within three) it is not allowed. Thus, if there is distinction between a regular talmid gamur and a talmid chaver, as the sugya in Eruvin implies, it must be even within three, as the Rama writes.

With this, perhaps we can also explain the Tosfot and answer our questions against him. Perhaps Tosfot also agrees with the Rashba's principle that there is no issue of kvod rabo beyond three parsaot, and it is only necessary to receive permission because of Rebbe's decree. However, he interpreted Rava's statement in Eruvin, "not in his presence is prohibited" to mean beyond three parsaot (unlike the Rashba), but not becaue of kvod rabo, but because of Rebbe's decree. In other words, Rava combined both laws in his statement. We must add that a talmid chaver is not subject to the decree of Rebbe, but only a regular talmid, as per the cases in Gemara Sanhedrin.

Thus, we can summarize the dispute between the three opinions as follows. The braita in Sanhedrin which implies that beyond three parsaot a talmid may rule without permission, applies, according to:

Tosfot -- only if he is a talmid chaver.

Rashba -- only as far as kvod rabo, but still needs authorization from someone.

Rambam -- only to rule occasionally.