Gemara

R. Tarfon was eating figs after most of the knives for cutting figs were stored away. (Figs are Hefker then.) The owner saw this, and put R. Tarfon in a sack. He was taking him to drown him in the river.

R. Tarfon wailed 'woe to Tarfon, that this man will kill you!' When the man heard whom he had seized, he fled.

(R. Avahu): The rest of R. Tarfon's life, he was pained that he had used the crown of Torah to save himself.

(Rabah bar bar Chanah): Anyone who uses the crown of Torah is uprooted from the world.

He learns a Kal va'Chomer from Belshatzar, who used Kelim of the Mikdash that had lost their Kedushah, and was killed, i.e. uprooted from the world. All the more so, one who uses the crown of Torah, which is eternal, will be uprooted!

Question: Why did R. Tarfon regret what he said?

Answer: R. Tarfon was very wealthy. He should have placated the owner by offering him money.

62b (Rava): A Chacham may say 'I will not pay the head-tax.' "Mindah, Balu,and Halach will not be placed on them (Kohanim)";

(Rav Yehudah): Mindah is the king's tax. Balu is head-tax. Halach is a tenth of all animals that the king takes.

Kesuvos 105b: Giving a gift to a Chacham is like bringing Bikurim.

Bava Metzi'a 84b: R. Elazar b'Rebbi Shimon's wife was angry that he had 'squandered' her father's money by bringing afflictions on himself; she left him. Some sailors were saved from great danger in R. Elazar's merit; they gave him a great gift. He told his wife 'my wealth exceeds that of your father's house' - "Haysah k'Aniyos Socher" (the Torah supports those who learn it).

Chulin 44b: R. Elazar would not accept gifts from the Nasi or invitations to eat there due to "V'Sonei Matanos Yichyeh";

R. Zeira declined gifts from the Nasi's house, but accepted invitations to eat there. He reasoned that they are honored by his presence.

Chulin 134a: A bag of money was sent to support Rabanan; R. Ami acquired it.

Question: "V'Nosan" - a person should not take for himself!

Answer #1: He acquired it on behalf of the poor.

Answer #2: The head (of the academy) may take for himself;

Beraisa: "Veha'Kohen ha'Gadol me'Echav" - the Kohen Gadol must be greater than the other Kohanim in beauty, Chochmah, and wealth;

Others say, if necessary, the other Kohanim give money to him to make him the wealthiest Kohen.

Rishonim

Rambam (Perush ha'Mishnayos Avos 1:13): One who intentionally is financed by and benefits from Torah will die. A Chacham may be served only by his Talmidim.

Rambam (4:5 and Hilchos Talmud Torah 3:10): "Haysah k'Aniyos Socher" - the Torah supports a Chacham who is physically unable to support himself. Otherwise, he may not take from others.

Rebuttal (Kesef Mishneh): If so, this is no praise of Torah! Sick and handicapped people always find people to support them, even if they are not Chachamim! Also, R. Elazar b'Rebbi Shimon brought afflictions on himself. He made his afflictions depart when he wanted to learn, but he did not do so to preclude the need to benefit from Torah!

Defense (Einayim l'Mishpat Bava Basra 110a:3): R. Elazar was concerned lest he needed a Kaparah for informing on sinners. Alternatively, he accepted on himself the afflictions due to come on Kelal Yisrael, so it was fitting to be supported by them.

Rebuttal (Kesef Mishneh): The Rambam connotes that a healthy Chacham should not take a gift. Giving a gift to a Chacham is like bringing Bikurim!

Defense (Einayim l'Mishpat ibid.): We learned that giving to a Chacham is like Bikurim from Elisha (Melachim 2:4:42), which was in a famine year. Perhaps it applies only when the Chacham cannot support himself!

Kesef Mishneh: It was customary to give gifts to Nevi'im (Shmuel 1:9:7-8).

Einayim l'Mishpat (ibid.): Since people give small gifts to an important person, even if he is ignorant, this is not considered benefit from Torah. Elisha (took a big gift, but he) himself did not benefit from the gift. He gave it to his Talmidim, who could not support themselves while learning.

Kesef Mishneh: When R. Ami took the money sent to the Beis Medrash (Chulin 134a), the question was only why he took it by himself rather than letting others give it to him.

Poskim

Rema (YD 246:21): If a healthy person plans to learn Torah, not work and receive Tzedakah, this is Chilul Hash-m and a disgrace to Torah. One who is old or sick may be supported by others. Some permit even if he is healthy.

Source (Gra 62): The latter opinion learns from the judges in Yerushalayim (Kesuvos 105a).

Yam Shel Shlomo (Chulin 3:9, brought in Taz 7): Tosfos (Bava Metzi'a 70b DH Tashich) says regarding the Heter to lend to Nochrim on interest 'Kedei Chayav' (for as much as he needs to live) that nowadays due to government taxes there is no limit. We can say the same to justify taking money to learn even if one has money. Even those exempt from taxes have great expenses to teach Torah to their children and to marry off daughters to Chachamim.

Taz (YD 246:21): One who is not overly wealthy may rely on this to take a gift of any amount, but not if he already has enough to last his lifetime.

Bach (DH u'Mah she'Chosav Kol): A Rosh Yeshiva may take gifts to become rich to give more clout to his words. We learn from the Kohen Gadol.

Question: The Gemara (Kesuvos 105a) was forced to say that judges in Yerushalayim received extra money only if their stipends did not suffice!

Answer (Bach DH v'Ha): Those judges had clout regardless of their wealth.

Rebuttal (Taz 7): If people may give gifts to the Av Beis Din, one might give a gift now (if he knows that he will have a judgment later) to bias the Av Beis Din! If one takes gifts, this will be his only reward for his Torah. Money hungry Chachamim who demand money disgrace Torah and those who learn it!

Rema (ibid.) Nevertheless, it is Midas Chasidus to support oneself and learn. This is a gift from Shamayim; not everyone can do so and become a Chacham.

Source (Gra 65): R. Elazar and R. Zeira declined gifts from the Nasi due to "V'Sonei Matanos Yichyeh".

Rema (ibid.): The Heter is to receive from the Tzibur, but not from individuals.

Shach (21): The Kesef Mishneh, Maharshal and Bach permit from people. "V'Sonei Matanos Yichyeh" does not imply that one who takes gifts will die.

Rema (ibid.): Giving a small gift to a Chacham is likened to bringing Bikurim. It is customary to give such gifts to an important person, even if he is ignorant.

Birkei Yosef (DH Kol): If the giver himself wanted to give, one who refuses to accept withholds Chesed. Shmuel ha'Navi did not take because he feared that people offered because they were embarrassed not to. Even though some Chachamim refused to take due to "V'Sonei Matanos Yichyeh", a traveler does not have his Kelim and is like an Oni, so he may take.