ויקרא אל משה…(ויקרא א:א)

And (Hashem) called to Moshe…

The Baal HaTurim explains why there’s a small “א” in the word ויקרא, because it reflects the humility of Moshe Rabbeinu.

The phrase “ויקרא” without the “א” is “ויקר” and the Gemara says that “ויקר” means Tefillin, “אלו תפילין שבראש” – these are the tefillin worn on the head – Hashem showed Moshe “וראיתי את אחרי” the knot from His tefillin.  And even though Moshe was revealed such greatness, he still kept a shallow profile. This message is reflected by the small “א” in the word “ויקרא”to allude that though Moshe Rabbeinu was on such an exalted level from seeing the “קשר (the knot) from Hashem’s tefillin” which is called “ויקר”, thus, he remained humble.