Our Gemara on Amud Aleph describes another invalid scenario of תעשה ולא מן העשוי: If there was a large pile of hay in a field and then one hollowed out a living space, “igloo style” inside the pile, it would not be kosher as a Succah. Even though the material is all kosher and the size is correct, since he hollowed out the internal space, the roofing Schach only came into being inadvertently.

Noam Elimelech (Bereishis VaYishlach 11) explains this Mishna allegorically. As we have discussed, the Succah represents God’s presence in the world and the hollowing out the pile of hay is symbolic of the Tzaddik’s wish to take a shortcut to benefit others. Meaning, the pre-existing structure that is being hollowed out is the opportunity for God and the world to be unified - as all the existing ingredients are there. However, there is a limitation of תעשה ולא מן העשוי, the structure cannot emerge passively but rather each person must make it. 

Even though the connection to God is pre-existing and complete from God’s side of things, in relation to this world it is something  that only each of us can forge and complete on our end to activate it. This is an important concept discussed in Eicha Rabah (1) (and developed further in Nefesh HaChayyim (1:3):

Rabbi Azarya said in the name of Rabbi Yehuda the son of Rabbi Simon: when the Jewish people do the will of the Omnipresent they add strength to heaven, as it states in Psalms (60:14) ”in Elokim strength is made.” However, when the Jewish people do not perform in accordance with the will of the Omnipresent, it is as if to say that they weaken the strength of heaven. As it states, (Deuteronomy 32:18) “You have weakened the one who has created you.“