Learning while entering a shul or beis medrash for other purposes

Question:

I know that there is a halacha that if one wants to enter a shul or beis medrash to pass through, or wants to enter not for the purposes of Torah and Tefillah, one may still do so if they learn something.

1. How much must one learn for the purposes of this halacha?
2. Also, does one need to sit down while doing the learning, or may he also stand?

Answer:

1. It is sufficient to say a posuk or to learn something. The point is that it should be considered going into the shul for a mitzva reason, and by learning something that is accomplished.
2. One does not need to sit down, however it is better to sit down. The reason being that then it is as if he went into the shul to do two mitzvos, learning, and sitting in the shul.

Sources:

Biur Halacha 151- 5 D:H La’asos, Ben Ish Chai 1 Vayikra 9, Kaf Hachaim 151-25,35, Chayei Adam 17-12, Bais boruch 17-81, Aruch Hashulchan 151-1.