In the song Lecha Dodi the author states סוף מעשה במחשבה תחלה - last in deed, [was] first in thought
I have seen this maxim attributed to Aristotle; is there a classic Jewish source for this in Tanacha, Chazal, Midrash etc?
First things that come up on a search are
The words "רִאשׁוֹן לַמַּחֲשָׁבָה, אַחֲרוֹן לְמַעֲשֶׂה.".
Ramban in the book believe and trust chapter 8