(Lev. 1:1:) “Then [the Lord] called unto Moses.” Let our master instruct us: When the one who leads the prayers makes a mistake by not saying the benediction on the cursing of the heretics (birkat haminim), from where do we know that it is necessary to have him repeat [the benediction]? Thus have our masters taught: When the one leading the prayers makes a mistake in any of the [other] benedictions, they do not have him repeat; [if he does so] in the [twelfth] benediction concerning the heretics, they force him to repeat it. We suspect that he may be a heretic and therefore have him repeat, so that if there is a heretical side to him, he will be cursing himself with the community responding, “Amen.” So also [do we treat] whoever does not say [benediction 14], "who builds Jerusalem," since they will suspect that he may be a Cuthite (Samaritan). R. Assi said, “If a proselyte takes upon himself [all] the words of Torah except for one, they do not accept him. And not only that, but [the same rule applies] even in the case of a single minute detail out of [all] the minute details in the Torah or out of the minute details from the scribes (rabbis). R. Judah bar Shallum said, “You find forty-eight times in the Torah where the Torah warns against [harming] the proselytes and, corresponding [to these forty-eight warnings], it warns against idolatry [forty-eight times as well]. The Holy One, blessed be He, said, ‘It is enough that he forsakes his idolatry and comes to you; therefore I am warning you about him, because I love him, as stated (in Deut. 10:18), “and [He] loves the proselyte in giving him food and clothing.”’”