Normally, a person who hears Kaddish or Nakdishach may respond even if he hears from a distance, and is not present with the Minyan. There are, however, exceptions to this rule.

The Shulhan Aruch writes that a person standing outside a synagogue may respond to Kaddish or Nakdishach, but then adds that according to some opinions, this is not allowed if there is "Tinuf" (filth, such as a trash can), or a non-Jew, in between him and the congregation. At first glance, it appears that the Shulhan Aruch here cites two different opinions, and according to the first opinion, one may respond even if there is "Tinuf" or a non-Jew in between him and the Minyan. If so, then we follow the general rule that the Shulhan Aruch accepts the first opinion when he brings two different views, and thus one may may respond regardless of what is between him and the congregation.

Hacham Ovadia Yosef, however, understands the Shulhan Aruch as clarifying his initial statement, and not as citing a dissenting view. Therefore, one may not, in fact, respond to Kaddish or Nakdishach if there is either "Tinuf" or a gentile in between him and the Minyan.

The word used by the Shulhan Aruch in this context is "Akum," an acrostic that refers either to an idol – "Avodat Kochabim U'mazalot" – or to an idolater – "Obed Kochabim U'mazalot." The Magen Abraham (Rav Avraham Gombiner, Poland, 1635-1682) understood that the acrostic "Akum" in this context refers to an idol, and not to a gentile. According to this reading, a non-Jew does not interrupt between a Minyan and a person listening from a distance, and he may respond. However, Hacham Ovadia notes that in earlier editions of the Shulhan Aruch, the word used in this passage was not "Akum," but rather "Goy." It is clear that the word was changed as a result of censorship, as Jewish communities needed to avoid giving the impression of looking disdainfully upon their non-Jewish neighbors, and so texts that might be misunderstood as such were occasionally emended. Hence, the Magen Abraham's reading is incorrect, and even the presence of a non-Jew in between a person and the Minyan creates an interruption, preventing him from responding.

Since the Shulhan Aruch used the word "Goy" – "gentile" – and not "Obed Kochabim" – "idolater," this Halacha applies to all gentiles, even to those who do not worship idols. The Rambam famously ruled that Muslims are not considered idol-worshippers, since they believe in a single Deity who created the world. For the purposes of this Halacha, however, the non-Jew's religious beliefs are irrelevant, and his presence is considered an obstruction regarding the ability to respond to Kaddish and Nakdishach.

The Magen Abraham and Mishna Berura asserted that the Rama (Rav Moshe Isserles, Cracow, 1530-1572) disputed this entire Halacha, and maintained that the presence of filth or of a gentile does not affect the ability to respond to Kaddish or Nakdishach. Nevertheless, Sephardic practice follows the Shulhan Aruch's ruling.

It must be noted that this entire discussion refers to the case of a person who is not inside together with the Minyan, and there is a gentile in between him and the Minyan. In such a case, the presence of the Shechina needs to extend from the Minyan to the person standing at a distance, and this extension can be obstructed. A gentile's presence inside the Minyan, however, has no effect whatsoever. If, for example, a political figure is visiting the synagogue, or a congregant has a non-Jewish aide helping him in the synagogue, it is certainly permissible for everyone to respond to all the prayers, even if the non-Jew stands in between a person and the Hazzan. Although there is an opinion among the Poskim that is stringent in this regard, the consensus follows the lenient position.

One example where this problem arises was noted by the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), who describes how it was common in Baghdad for merchants to display their wares in the hallways of synagogues. If a person was in the hallway of such a synagogue, he needed to ensure that the non-Jewish merchant was not standing in between him and the sanctuary. Another situation where this could arise is an airport. If ten men find an area to pray, and someone joins their Minyan from a distance, he may not answer unless he ensures that no gentiles come in between him and the Minyan. This could arise also when a person hosts a catered event in his home, and a Minyan is formed in the living room. If someone wishes to participate in the Minyan from the kitchen, he must ensure that non-Jewish workers are not standing in between him and the Minyan.

Some Poskim place a very significant limitation on this entire Halacha, maintaining that it applies only if the person can see the "Tinuf" or the non-Jew in between him and the Minyan. But if, for example, a person lives near a synagogue, and he hears the prayers through the window, then he may respond even if there is "Tinuf" or a gentile in between. This is the view taken by the Gaon of Vilna (1720-1797) and by Rav Shlomo Zurafa (Algeria, 1785-1859). Although others seem to disagree with this ruling, it is accepted as Halacha by Hacham Ovadia Yosef, in Yehaveh Da'at, and by his son, Hacham David Yosef, in Halacha Berura.

This Halacha becomes relevant in the case of a person who hears a live broadcast of a prayer service. Some congregations arrange a livestream of the Tefila for the benefit of those who are unable to attend due to health reasons, or for those in remote areas without a Minyan. The accepted Halacha is that although one cannot fulfill his obligation to recite a text – such as the reading of Megilat Ester on Purim – by listening via telephone or some other communication system, one can respond to Berachot, Kaddish and Nakdishach if he hears the recitation through a live broadcast. Quite obviously, there is "Tinuf" and gentiles in between the individual listening to a broadcast and the synagogue miles away where the prayers are being recited. Nevertheless, Hacham Ovadia ruled that one may respond, in light of the aforementioned ruling that everything in between may be disregarded if it cannot be seen.

A Minyan may be formed even though non-Jews live in the same building, above the Minyan. Hacham Ovadia writes that there is no source whatsoever for the notion that the presence of gentiles above a Minyan obstructs the prayers from ascending to the heavens. Therefore, it is entirely permissible to pray on a ground floor even though gentiles are present above the Minyan.

Summary: If a person hears Kaddish or Nakdishach from outside the area where the Minyan takes place, he may respond, unless there is "Tinuf" (filth) or a non-Jew in between him and the Minyan. If, however, the "Tinuf" or the gentile cannot be seen – such as if a person hears a Minyan from a window in his home – then he may respond. Therefore, a person who hears a Minyan via livestream may respond. A gentile's presence in the synagogue, or in the area where the Minyan is held, has no effect, and everyone in the room may respond.

More lectures from Rabbi Eli Mansour

Beki'im BaHalacha - Hilchot Berachot: Preface - Netillat Yadayim - Washing Hands to Eat Bread

The Special Significance of Kaddish

Situations Where One May Not Respond When Hearing Kaddish or Nakdishach

Beki'im BaHalacha - Hilchot Berachot: Safek Berachot Lehakel - Halachot - 15-16

Is One Credited With Praying With a Minyan If He Prays in a Different Room?

Parashat Bo