Sefer Ha’mitzvos Ha’Katzar (the concise book of mitzvos)
By the Chofetz Chaim
This book lists the Torah mitzvos that can be observed today
First Section – the Positive Commandments
18. It is a positive commandment to have awe in the Sanctuary
As it says in Vayikra (Leviticus) 19:30, “And you shall have awe of My Sanctuary.” Our synagogues and Batei Midrashos (houses of Torah study) are called small Sanctuaries, as it says in Yechezkiel (Ezekiel) 11:16, “I have been to them as a small Sanctuary.” We must be careful in them to avoid laughter, levity, or idle speech. We should not conduct business in them, nor sleep in them. Their holiness is very great.
This is obligated in all places and at all times, for men and for women