Scriptures state that Brahman is the First cause

I.1.11
श्रुतत्वाच्च |
Shrutatvaaccha

And because it is directly stated by the Srutis, the all knowing Brahman is the first cause of the universe

Shrutatvaat(श्रुतत्वात्): being declared by the Sruti; cha(च): also, and.

Svetasvatara Upanishad VI-9: 
He is the cause, The Lord of lords of organs. He has neither parent nor lord


Commentary:
HE refers to the all knowing Brahman(GOD). Therefore it is finally established that the All-Knowing, All-Powerful Brahman is the First Cause and not the insentient or non-intelligent Pradhana or anybody else

Background

Introduction - part1, part2, part3, part4

Sutra - I.1.1, I.1.2, I.1.3, I.1.4, I.1.5, I.1.6, I.1.7, I.1.8, I.1.9, I.1.10

Pradhana cannot be the source - III

I.1.10
गतिसामान्यात् |
Gatisaamaanyaat

On account of uniformity of view of the scriptures, Brahman is to be considered as the first cause

Gati(गति): view; saamaanyaat(सामान्यात्): on account of uniformity;

Commentary:
Kaushitaki Upanishad III-3
Just like sparks proceed in all directions from a burning fire, from the self everything else will proceed


Taittareya Upanishad II-1
All this(manifestations) springs from the self


Prasna Upanishad III-3 
This Prana is born from the self

all the above passages describe the Self to be the cause. Therefore the all-knowing Brahman should be considered as the first cause because of the uniformity of the view of the scriptures

Background

Introduction - part1, part2, part3, part4

Sutra - I.1.1, I.1.2, I.1.3, I.1.4, I.1.5, I.1.6, I.1.7, I.1.8, I.1.9