Just when His great masterpiece of heaven and earth was finally up and running, G_d realized there was something missing: The autograph.
Without an autograph, the creatures of this world might take life, beauty, pleasure and all the other amenities of existence for granted. They could fail to take care of the home made for them, even turning reckless and destructive.
So He left the autograph up to us. Our job is to make it recognizable that this is actually the ultimate piece of art, crafted by the ultimate of all artists, the Master Designer/Architect/Engineer of all things.
In Hebrew, we call this a Kiddush Hashem—roughly translated as Sanctification of The Name (English is kind of clumsy with these things). How do we make aKiddush Hashem? Well, as you may have guessed from the sound of the words, making "kiddush" on wine on Friday night as Shabbat enters is one great way. So is any act that demonstrates a higher purpose and meaning to life, whether that be a public prayer, an act of charity or just everyday acting like a mentsch.
Of the prayer-forms of Kiddush Hashem, the most extreme example is theKaddish1. No other words we say in all our prayers are attributed the same level of sanctity.2
FOOTNOTES 1.
See introduction to HaKaddish, Rabbi Dovid Assaf (Hebrew)
2.See Shulchan Aruv HaRav, Orach Chayim, 56:1–2