I have previously explained that Massechet Yevamot contains much material about conversion, and given this, I would like to make reference to a teaching from the Beraita about Jewish conversion policy found in today’s daf (Yevamot 24b) where we are taught that אין מקבלים גרים לימות המשיח – ‘conversions won’t be performed in the Messianic era’ (i.e. when Jews will not be persecuted), and כיוצא בו – ‘similarly’, לא קבלו גרים לא בימי דוד ולא בימי שלמה – ‘conversions weren’t performed either in the time of David or Solomon’s reign’ (i.e. when the Jewish people were strong and could overcome their enemies). And what is the reason for this conversion policy? It is seemingly due to two reasons, which – though they don’t necessarily manifest themselves together – are both fundamental demands for a convert: sincerity, and loyalty.
In terms of ‘sincerity’, our Gemara expresses concern that when life seems attractive as a Jew then some non-Jews may be attracted to convert even though they don’t sincerely want to be Jewish. Interestingly, we have a tradition that when the many miracles that we recount on Seder night were wrought on the Jewish people, Moshe made the decision to allow a large group of Egyptians to covert to Judaism (to become what is known as the ‘Erev Rav’). However, we are later taught that it was the Erev Rav who led the efforts to build the Golden Calf, which is why – as the Or HaChaim explains (in his commentary on Shemot 32:10) – God chided Moshe, “your people, whom you brought out of Egypt, are acting ruinously” (Shemot 32:7). Given all this, it was decided that to avoid the repeat of past mistakes, conversions wouldn’t be performed when life looks good for a Jew such as during the reign of David, Solomon and in the Messianic Era.
However, there is a second reason for this policy relating to ‘loyalty’, which is that being a Jew isn’t just about being proud of Jews and Judaism when things are going well and when Jews are not being persecuted, but also about standing by Jews and Judaism when things are tough and when your brethren are being persecuted. As Rav Soloveitchik explains, ‘The Jew who believes in Knesset Israel is the Jew who lives as part of it wherever it is and is willing to give his life for it, feels its pain, rejoice with it, fights in its wars, groans at its defeats and celebrates its victories’ (On Repentance p. 62).
Yet there is a difference between these two reasons, because while both are demands of a convert, and while the former doesn’t apply in its strictest sense to a Jew from birth, nevertheless, and as emphasized by Rav Soloveitchik, the latter does.