עקב אשר שמע אברהם בקולי - Formative Years of Nothing

 

עקב אשר שמע אברהם בקלי וישמר משמרתי מצותי חקותי ותורתי

The zohar (found as an addendum to Parshat Behalotcha daf 151a here) understands the chazal

 בן שלש שנים הכיר אברהם את בוראו - as being a reference to three formative sefirot of כתר חכמה בינה - (the gematria of ספירה=שנה).  

He explains that Avraham couldn't reach his level of Chesed in Malchut but only through those 3 sefirot first. Only then 172 years of true שמע בקולי וישמור משמרתי וכולי

The beauty in the seeming "formative nothingness" of a child's first 3 years akin to the beauty of "formative nothingness" in a man's focusing on his inner existensial self, irrespective of the world outside of him in which he acts and interacts with. (the sefirot of כח"ב being the internal מוחין versus the other 7 that interact with an outside world)

I would just possibly add that the zohar may have intended to further posit that the word of אשר being a reference to those 3 sefirot as well  (א- כתר, ש - בינה, ר - חכמה) - in which case you then have the entire 175 years of אברהם being referred to in the pasuk עקב אשר שמע אברהם בקולי