Ask the Rov: How can I tidy the shul Shabbos afternoon and return the seforim to the shelves?
By Rabbi Chaim Hillel Raskin – Rov of Anash in Petach Tikvah
When dealing with a mixture of two types of food, the melacha of borer necessitates selecting specifically the one you want from the one you don’t, by hand, and for immediate use. The same rules apply to a mixture of non-food items as well.1 Sorting between two types of things to use both later is also prohibited (see issue 326).
If one of the types of foods or items is larger, making it distinct from the other type in the mixture, it is doubtful whether it constitutes a true mixture for borer purposes. Nevertheless, the Alter Rebbe rules stringently since it is a potential Torah transgression.2
Seforim standing upright on a shelf are not considered “mixed,” and one may select a book even for later use.3 Some require the sefer’s name to be recognizable on its binding and for there to be sufficient light in the room to see the titles.4 The same is true for seforim that are lying neatly on the table in a way that one could easily select the one he wants.5
Disorderly seforim on the table are considered mixed, and if they belong to different types— even siddurim of different nuschaos or styles—one may not sort them for later use. Yet, if a sefer you wish to use now is at the bottom of a pile, you may remove the top seforim, leaving the one you want accessible. This isn’t considered separating a mixture, but instead removing an impediment, like peeling a fruit to eat.6
What about taking the top sefer, putting it on the shelf, and then continuing through the rest of the pile, one sefer at a time?
Some allow this, since you only take one sefer in your hand each time, and once you are holding it, you may put it wherever you want.7 However, most contemporary poskim forbid it since your overall activity is sorting the seforim,8 and one should be stringent. However, one may take the top sefer to learn a bit, put it in its correct place on the shelf, and proceed to learn the next one. Yet, it should not be obvious to onlookers that one is trying to circumvent the borer prohibition.9
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From The Weekly Farbrengen by Merkaz Anash