In the beginning of this week’s parshah, Hashem commands Moshe to count Bnei Yisrael by counting the half shekels they donated. Rashi explains that Hashem did not want Moshe to actually count the Bnei Yisrael directly.
The Gemara (Berachos 62b) says that Hashem said to David Hamelech that he would test him with something that even school children know, but did not reveal to him what that would be. The Gemara then quotes pesukim from the beginning of this week’s parsha from which we derive that it is forbidden to count Bnei Yisrael. But David Hamelech stumbled in this regard and counted Bnei Yisrael (Shmuel II 24:1).
The Ramban (in his commentary on this week’s parshah) explains that David Hamelech thought that the prohibition not to count the people of Bnei Yisrael was a one-time prohibition. He didn’t know it applied to all times.
It is evident from this Gemara that the pesukim in the beginning of this week’s parshah are the source for not counting Bnei Yisrael. It is therefore curious that the Gemara in Yoma 22b cites a pasuk from Navi to source this prohibition.
The Gemara in Yoma says there was a lottery to determine who would get to do certain tasks in the Beis Hamikdash. The lottery was cast by counting the fingers of the kohanim. The Gemara asks why the kohanim themselves couldn’t have been counted. Why did they have to count their fingers? The Gemara answers that it is forbidden to count Bnei Yisrael even for mitzvah purposes, as it says in Shmuel 1:15. The Gemara then says in the name of Rabbi Elazar that counting Bnei Yisrael is forbidden and cites a pasuk in Hosheiya (2:1) as the source.
The Maharsha asks why the Gemara did not quote the pesukim in the beginning of this week’s parsha as the source for this prohibition. Why did the Gemara quote pesukim in Navi instead of the Torah?
The Maharsha answers that from this week’s parshah it is not evident that there is an aveirah to count. The pesukim in Navi, in contrast, indicate clearly that it is prohibited to count Bnei Yisrael.
The Iyun Yaakov (a pirush on the Ein Yaakov) answers that from the pesukim in the beginning of this week’s parshah it is not evident that one may not count Bnei Yisrael for mitzvah purposes. From our parshah it is only clear that one may not count Bnei Yisrael for a davar reshus. The Gemara in Yoma concerned counting for a mitzvah, which is why the Gemara brought sources that prove that it is forbidden even for mitzvah purposes.
But why then were kohanim allowed to be counted in the Beis Hamikdash via their fingers? Why is counting fingers different from counting people?
The Pardes Yosef answers that the pasuk says not to count “es rosh Bnei Yisrael” – the heads of Bnei Yisrael. Counting heads is prohibited but counting fingers is permitted.
The Chasam Sofer (Kovetz Teshuvos 8) and Rav Moshe Feinstein (Yoreh Deah 3:117) cite the Rambam that opines that a kohen could have put out more than one finger. And even according to Rashi who opines that a kohen was only permitted to put out one finger, still he could choose to not put out any fingers at all. Therefore, the count was not precise or necessarily accurate. Therefore, it was permitted to count in this way because the count did not reflect an accurate number of people.
Based on this it should be forbidden to count people in shul to determine if there is a minyan. There is a minhag brought in the Kitzur Shulchan Aruch (15:3), however, to count people by reciting a pasuk that has 10 words.
Why, though, is this permitted? This should be considered counting people.
The source for this minhag is the sefer Haorah 1:56 (which some attribute to Rashi). There it is written that when people wanted to know if they had a minyan, one person would say the first word of a pasuk that had 10 words, then another person would say the next word, and a third person would say the next word, etc. etc. If the pasuk was completed they knew they had a minyan. This practice, however, differs from the minhag of one person counting by means of reciting a 10-word pasuk.