Gemara

(Rav Yehudah): Four categories must thank Hash-m [after being saved from danger]: one who was at sea, one who was in the desert, a sick person who recovered, and one who was released from prison;

They say "Baruch Gomel Chasadim Tovim."

(Abaye): They must bless in front of 10 people -- "vi'Romemuhu bi'Kehal Am."

(Mar Zutra): Two of them must be Chachamim -- "uv'Moshav Zekenim Yehaleluhu."

Objection (Rav Ashi): We should require all of them to be Chachamim!

Answer: It does not say "bi'Kehal Zekenim," rather, "bi'Kehal Am"!

Question: We should require 10 regular people, and additionally two Chachamim!

Kashya (this is left difficult).

Rav Yehudah fell sick and recovered. R. Chana Bagdata'ah and Rabanan visited him, and blessed Hash-m for his recovery.

Rav Yehudah: You exempted me from thanking Hash-m.

Question: Abaye taught that one must bless in front of 10!

Answer: There were 10 there.

Rishonim

Rif and Rambam (43a and Hilchos Berachos 10:8): They must bless in front of 10. Two of them must be Chachamim.

R. Yonah (DH Amar): We learn from the episode with Rav Yehudah that the Choleh is not Yotzei with another's Berachah if less than 10 were there. However, they may bless without 10, even though he is not Yotzei through it.

R. Yonah (DH Arba'ah): Rav Hai Gaon said that Rav Yehudah did not teach them in the order of the verses. He listed first those that are more dangerous. Those who traverse the sea or Midbar are in more danger than a Choleh, for most Cholim get cured. Most people are imprisoned for monetary reasons, and there is not such danger. The verses mention first what is most common.

Rosh (9:3): The Gemara asked that we should require 10 and two Rabanan, and did not resolve this. Therefore, we are stringent and we require both of these. The Rif did not say so.

Question: If one was imprisoned for a fixed tax that is the same for everyone, does he bless ha'Gomel? Or, is it only for one was imprisoned for a matter that entails danger?

Answer (Ri mi'Gash 90): Since he was imprisoned, and he had no autonomy, and now he was freed and has autonomy, he must bless. This is especially if he was imprisoned for a fixed tax or debt that he was unable to pay, and Hash-m enabled him to pay it. Chachamim said that one who was imprisoned and was freed must thank. They did not distinguish whether he was imprisoned for monetary or capital reasons. This excludes one who could have paid the tax or debt, and he refrained due to rebelliousness, or he hoped to be pardoned, but did not succeed. He caused himself to be imprisoned, so he should not bless on this, unless we say in such cases "[if so,] the law varies" (it is more reasonable to say that Chachamim made a uniform law).

Kaf ha'Chayim (12): If he could have paid, also Ben Ish Chai says that he does not bless. Sha'arei Teshuvah says that he blesses without Shem and Malchus.

Poskim

Shulchan Aruch (OC 219:1): Four categories must thank Hash-m: one who was at sea, in the desert, or was sick, and one who was released from prison.

Magen Avraham (1): This refers to one who was imprisoned for capital matters.

Birkei Yosef (4): R. Yonah says oppositely in the name of Rav Hai Gaon, that most people are imprisoned for monetary reasons. It seems that the Aruch agrees. He says that 'one released from prison' is even if he was imprisoned due to taxes, which is less dangerous than all the rest. The Ri mi'Gash says that anyone who was imprisoned and freed must bless. Eliyahu Rabah brings from R. Yonah unlike the Magen Avraham. This is the custom, that anyone imprisoned blesses.

Mishnah Berurah (3): If one was obligated to bless due to all four reasons, he blesses only once for all of them.

Bi'ur Halachah (DH Chavush): The Magen Avraham connotes that the Chiyuv to thank is due to the danger of being imprisoned. Therefore, if he was imprisoned for monetary reasons, so there is no mortal danger even if he cannot obtain the money, one does not bless. If so, in a capital case one blesses only if he was confined before there was a final verdict, for then there was danger. If there was already a final verdict of a prison sentence, even if there was a capital accusation, since this is the only punishment, there was no danger, so he does not bless (unless being in such a prison is dangerous). Or, perhaps he must thank Hash-m that he was not sentenced to die. The Magen Avraham holds that the Meforshim the Birkei Yosef brought hold like the Aruch, who obligates blessing even for a small pain but the Mechaber (Sa'if 8) does not hold totally like the Aruch. The Mechaber obligates only if he was bedridden, for this often leads to danger. According to the Rema and the Ashkenaz custom, the Magen Avraham is correct.

Kaf ha'Chayim (11): Chikekei Lev says that if he was imprisoned in the dignified prison due to a debt, he does not bless. If he was imprisoned in the disgraceful prison, even due to monetary matters, he blesses. However, the custom is like the Ri mi'Gash, to always bless.

Kaf ha'Chayim (13): Some say that if he escaped, and if they catch him they will punish him, even so, he blesses. The Birkei Yosef (Shiyurei Berachah) disagrees. This is unlike one who found a lost object. (Even though if the king finds out, he will lose everything, he blesses Shehecheyanu or ha'Tov veha'Metiv - 222:4.)

Eliyahu Rabah (12): Keneses ha'Gedolah was astounded why women do not bless. He said that they should bless in front of 10, or at least in front of one man or women. If she blessed by herself, she was Yotzei. I say that a woman does not bless because she is punished primarily due to her husband (Shabbos 32b). It is best that her husband say "Baruch Atah Hash-m Elokeinu Melech ha'Olam Asher Gamlech", and she answers Amen. I concluded that her relatives should not bless, but here one may rely on the Poskim who permit, for one's wife is like himself.

Birkei Yosef (2): A woman should bless in the Ezras Nashim, and men will hear in the Beis ha'Keneses. Or, at least women and one man will hear her.

Mishnah Berurah (3): The custom is that women do not bless, for it must be in front of 10 [men], and this is improper for women. Some say that in any case it is proper that she bless in front of 10, in any case in front of women and one man.

Kaf ha'Chayim (3): Keneses ha'Gedolah permits if women or one man will hear her. We are concerned for the opinion that it is a Berachah l'Vatalah if it was not in front of 10 men. Therefore, she may bless only in front of 10 men, but this is improper, therefore she blesses in the Ezras Nashim and men hear her, or she blesses in front of her relatives and acquaintances. If not, she blesses without Shem and Malchus.

Igros Moshe (5:4): Intrinsically, there is no reason to distinguish men from women. However, Chachamim were stringent to bless only in front of 10, and on a day of Keri'as ha'Torah, and when he is called to read from the Torah. If he cannot be called to the Torah, he blesses at the Bimah right after Keri'as ha'Torah, even though it is not connected to Birkas ha'Torah. This is like the Berachah that a father says when his son become Bar Mitzvah) "Baruch she'Patrani me'Onsho Shel Zeh." Nowadays it does not apply to women, for they do not read from the Torah.

Magihah: This was the last Teshuvah that R. Moshe Feinstein wrote. It was very difficult for him to write it. He added verbally 'this is unlike the Mishnah Berurah, who says that she must bless in front of 10, or at least in front of women and one man. There is no significance to a Minyan (number; perhaps this refers to 10 - PF) of women. It suffices to bless in front of one person, be it a man or woman. L'Chatchilah, a married woman should bless in front of her husband.'

Shulchan Aruch (3): One blesses in front of 10, and two of them must be Rabanan.

Beis Yosef (DH Kasav): The Rif, Rambam and Semag hold that the two Rabanan are among the 10. Tosfos requires 10 excluding the two Rabanan. It seems that the Rosh agrees. The others are lenient, for this law is mid'Rabanan. The case with Rav Yehudah connotes that it suffices to have 10 in all.

Gra (DH Trei): This is like the Rif, that when the Gemara concludes 'Kashya', the law is not refuted.

Gra (DH v'Im): According to Tosfos, the Gemara did not ask from Rav Ashi (who requires 12), since this is not Me'akev.

Kaf ha'Chayim (4): L'Chatchilah, one should fulfill the stringent opinion and require 12.

Mishnah Berurah (6): The one who blesses counts towards 10.

Kaf ha'Chayim (19): Some say that he does not count. Chayei Adam and Kitzur Shulchan Aruch rule like them.

Magen Avraham (3): The Rabanan must teach Halachos.

Shulchan Aruch (ibid.): If Rabanan are not commonly found, he blesses anyway.

Source: Mordechai (212), cited in Beis Yosef DH v'Chasav.

Shulchan Aruch (ibid.): The custom is to bless after Keri'as ha'Torah, for then there are 10. If he blessed with less than 10, opinions differ about whether or not he was Yotzei, so he should bless again without Shem and Malchus.

Beis Yosef (DH v'Im): The Tur says that he was Yotzei even there were not 10. He derives this from the Gemara. I say that the Gemara connotes that 10 is Me'akev! R. Yonah holds like this.

Gra (DH Yesh): The Tur holds like Rashi (15a DH Ela Rebbi), who says that whenever it says 'Tzarich', it is not Me'akev.

Gra (DH v'Yesh): In many places, it says 'Tzarich' and it is Me'akev.

Kaf ha'Chayim (26): Blessing quietly is like blessing not in front of 10.

Mishnah Berurah (8): It is only l'Chatchilah to bless in front of 10. If one knows that he will not be able to bless in front of 10, he blesses not in front of 10 l'Chatchilah.

She'elas Rav (ha'Gaon R. C. Kanievsky Shlita, 2:20:9): It is better to bless ha'Gomel himself than to be Yotzei through hearing it.