Dear Sister Noora,
First of all, I am not a fan of Rumi at all. His poetry is loaded with SHIRK, psychological complexes against the exalted Prophet and hatred of his noble companions.
CHOON SAHABA HUBBE DUNIYA DASHTAND
MUSTAFA RA BAY KAFAN BAGUZASHTAND
[Since the companions were drenched in the love of this world, they left alone the body of the Prophet (S) even without a coffin of cloth]
In my view, Rumi was a Criminal of Islam. Allama Iqbal only speed-read some parts of Rumi and failed to notice what his PIR (guide) had said.
"MUST ALAST" (duped in ALASTU) is a form of meaningless Sufi chanting. They vicariously connect it to the Qur'an.
ALASTU = Am I not?
ALASTU BIRABBIKUM? = Am I not your Sustainer?
7:172 When your Lord brought forth generations in succession from the Children of Adam, and made them bear witness, “Am I not your Sustainer?” They said, “Yes, we bear witness.” Thus you cannot say on the Resurrection Day, “We were not aware of this.”
[Min Zuhoorihim = From their posterity = In succession = Their seed = One generation following another. The Q & A here is an allegory. The uninterrupted survival of mankind is a telling witness that there is an Almighty Sustainer of them all]
I hope you get your answers from a lifelong student.