The concept of Hiddur Mitzvah is derived from Rabbi Ishmael’s comment on the verse, “This is my God and I will glorify Him” (Exodus 15:2)
“Is it possible for a human being to add glory to his Creator? What this really means is: I shall glorify Him in the way I perform mitzvot. I shall prepare before Him a beautiful lulav, beautiful sukkah, beautiful fringes (Tsitsit), and beautiful phylacteries (Tefilin).”