Tosefet Bracha - Vayikra

“He called (Vayikra) to Moshe” (1; 1)

The Ba’al HaTurim on this verse explains that the letter aleph of Vayikra is small so that it will look like the word vayikar (happened). Moshe wanted to have the language of happenstance which shows that G-d just came incidentally to the prophet, like it says regarding Bilam (Bamidbar 23; 4) “G-d happened (vayikar) upon Bilam”. Therefore Moshe asked G-d to write a small aleph in the Torah.
This is a very difficult comment of the Ba’al HaTurim. We find many times that the word Vayikra is used regarding Moshe. For example in Yitro (Shemot 19; 3), Mishpatim (Shemot 24; 16). In addition, why would Moshe want to be similar to Bilam in this regard? Especially as the Sages learn the word vayikar to imply many disgusting things – look at Rashi there, and the Zohar parshat Balak page 210b.
However we can explain the hint of the small aleph according to a comment of the Shach on Yoreh Deah 245; 8 in the name of the Kol Bo. He writes in the name of ‘the Rabbis said’ that we begin teaching children from Vayikra, because G-d has said, let the pure children come and learn the section that deals with purity. Perhaps it is to this that the small aleph alludes (to the small children learning (aleph means to learn).
The Shach and the Kol Bo didn’t bring the source for this custom. We should point out where it comes from. It says in the Midrash Tanchuma on parshat Tzav (14): Rabbi Asia said, why do the children begin learning from Vayikra? Because all the sacrifices are written in it. Since they are pure and don’t know the taste of sin, therefore G-d said that they should begin learning the section that deals with sacrifices. Let the pure ones come and involve themselves with the process of purification (through sacrifices) and I will consider it as if they were standing and offering the sacrifices before Me. This teaches you that since the destruction of the Temple when we have no more sacrifices (which keep the world in existence), if it were not for the children learning the parshiot of sacrifices the world would not be able to exist.
It is therefore correct that the Shach brought this statement in the name of the Kol Bo in the name of ‘the Rabbis said’, since it is in fact from Rabbi Tanchuma the author of that Midrash. He was one of the great Amoraim mentioned many times in both the Yerushalmi and the Midrash Rabba.
Look also regarding this at the Zohar on parshat Vayechi (234b) and on parshat Tzav (239a) on the verse “This is the Torah of the Olah, the Mincha and the Chatat” (7; 37).
Regarding this custom of beginning to teach the children from Vayikra the Shach writes that this is still the custom today (and he lived t the beginning of the 17th century). However, nowadays, we have lost this custom, along with so many of the ancient and beautiful customs of earlier generations, and they shall never be heard of or seen again.