Q. Honorable Rov. I have another question. Why do we assume in principle that the counting of the Omer is a positive time bound mitzvah from which women are exempt, more than the lighting candles, resting, eating and honouring Shabbat, that women do comply with?
A. The Ramban, (Chidushim to Kiddushin 33b) lists Sefirat HaOmer among the positive mitzvot that are not timebound, yet he doesn’t address the issue of whether women are obligated to count the Omer.
Ramban’s deviation from the mainstream view that counting the Omer is a timebound mitzvah puzzles most commentaries. Perhaps Ramban holds that Sefirat HaOmer is a rabbinic mitzva, instituted during post and pre-Temple times, therefore making it clearly not time-bound: “…you shall not turn aside from that matter that [the sages] tell you” (Devarim 17:11), explains Ramban’s position on Sefirat HaOmer.
Rabbi A. Bartfeld as revised by Horav Hirshman, Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit’a.