Why should I buy a special Esrog?

Remember: Tubeshvat is the time to daven for a special Esrog.

The pusuk says, "This is my God and I will glorify him", what does it mean to glorify Hashem, to glorify the Mitzot.  This is one of the sources to explain why we buy a beautiful Esrog, and special Tefilin.  When we do the mitzvot in a special way, we are really glorifying ourselves.

from a Shiur on Naaleh:

Parshat Beshalach: Glorifying the Glorified

Teacher: Mrs. Shira Smiles