According to the Seifer haYetzhirah, creation is made of words. And in Hebrew too, the word for speech when we are focusing on ideas is "דבר - dibbur", the same root as the word for "thing" -- "דבר - davar".
The Baal Shem Tov says that the first chapter of Bereishis uses the metaphor of Hashem speaking for a reason. One writes the written word, and then it continues to exist on the page. A spoken word exists as long as it is being spoken. If there is still light, it is because Hashem is still saying (as it were) "Yehi Or - Let there be light!". In fact, dibbur of "Yehi Or" is the davar we perceive as light.
Flipping to what most people think of as the far side of Jewish Thought from the Baal Shem Tov....
In the Rambam's model (Yesodei haTorah ch. 2) Hashem had a Thought, which had a thought, etc... A chain of intellects that runs down the various classes of angel through the spheres, and eventually down to us. Stating that idea in the words I established above, Hashem's dibbur is a medabeir ("speaker") which therefore itself has a dibbur… And so on down to the physical devarim (things) of this world.
In Qabbalah's model, the Or Ein Sof (the Light of the Infinite One / the Infinite Light) "descends" from world to world, getting implemented in ever more coarse forms.
I feel a need to buttress the presumption that we can use the Seifer haYetzirah, which reads like a mystical text but had rationalist interpreters like Rav Saadia Gaon, the Baale Shem Tov and the Rambam as description of the same ideas in different terminologies. Since, as I noted, people think of them as opposite sides of the Mystic - Rationalist spectrum. However, the Leshem (Rav Shelomo Elyashiv, 1841-1926, not to be confused with his grandson R' Yosef Shalom), in his Kelalim, argues that the similarities are there because these are indeed two different models of same Truth. And he manages to write a work of the Vilna Gaon's school of Qabbalah that regularly buttresses its points with citations from the Rambam's Moreh Nevuchim, Hilkhos Yesodei haTorah, and other writings.