Why We Need To Worship Nirguna Brahman?
Saguna Brahma and the Nirguna Brahman are actually two levels of worship for two kinds of people. Simply terms, the saguNa worship means worshipping a divine form with Guna's or attributes like name, shape, the special powers .And worshiping Nirguna brahman is meditating on our self or atman and knowing that Atman is brahman i.e. remaining in Non-Dual state.
In a work attributed to Adi-Shankaracharya called Nirguna Manasa Puja he is talking about Nirguna Brahma Upasana. We find the answer there .According to shankara meditating on Atman (Nirguna) Brahman is real Bhajan ,kirtan ,Shravan Samadhi etc.
Here he is saying that knowing that our self or Atman is Brahman is the real worship of Brahman. And the person should know that its him (Atma) is the one whch is to be worshiped /meditated
विश्ववन्द्योऽहमेवास्मि नास्तिवन्द्यो मदन्यतः।
vishvavandyo.ahamevAsmi nAstivandyo madanyataH
ityAlochanamevAtra swAtmali~ngasya vandanam..
I am the one who has to be revered in the universe, and none else.
Such an idea is the real salutation for the Atman.
In next shloka its said that that being meditating on Atman which is beyond any attributes is real Nama-Sankirtana ,Bhajana etc.
आत्मनः सत्क्रिया प्रोक्ता कर्तव्याभावभावना ।
नामरूपव्यतीतात्मचिन्तनं नामकीर्तनम् ॥20||
AtmanaH satkriyA proktA kartavyAbhAvabhAvanA.
in the idea of non-existence of duty is the real honour, and
meditating on the Atman which is beyond name and form is the real
singing of names.
श्रवणम् तस्य देवस्य श्रोतव्याभावचिन्तनम्।
shravaNam tasya devasya shrotavyAbhAvachintanam.
Realization that there is nothing else to be known (apart from the
Atman) is the true shravaNam (understanding of the text), and
realization that there is nothing else to be contemplated upon is
mananam (contemplation) in the true sense.
ध्यातव्याभावविज्ञानं निदिध्यासनमात्मनः ।
नान्यच्चित्तस्य विभ्रमः ।
तत्रैव ब्रह्मणि सदा
samAdhirAtmano nAma nAnyachchittasya vibhramaH.
tatraiva brahmaNi sadA chittavishrAntiriShyate..
The awareness that there is nothing else to be contemplated upon is
the true assimilation of knowledge, and staying in one self by total
absence of delusion and divergence is Samadhi. It is a state of
constant absorption of mind in the brahman (the first and second
sloka-s are to be read together).
And why we need to worship Nirguna Brahman is answered in this verse. Its said that meditating on Atman (self as Nirguna Brahman ) as described in vedanta the results of good or bad effects of karmas will not bind a person and his avidya (ignorance ) will disappear and thus his miseries ,and he will attain the bliss of Moksha.
क्षणं वा सुसमाहितः॥24||
सर्वदुर्वासनाजालं पदपांसुमिव त्यजेत् ।
विधूयाज्ञानदुःखौघं मोक्षानन्दं समश्नुते ॥25||
kShaNaM vA susamAhitaH..
sarvadurvAsanAjAlaM padapAMsumiva tyajet.
In this manner, a person with equanimity, by worshiping the Self as
visualized in the vedAnta shAstra, either for a moment or till his
death, will shake off the accumulated results of good and bad deeds
like the dust on the feet, and likewise will throw off the multitude
of miseries caused by ignorance and thus attain the Bliss of
So according to Shankara Advaita knowing Self is Brahman and meditating on Nirguna Brahman is real form of worship ,bhakti etc. one can attain Moksha through this kind of meditation. All his ignorance will disappear and he will experience pure bliss. And this is why we need to worship Nirguna Brahman.
We can read full NirguNa-MAnasa-PUjA Of Sri Adi Shankaracharya
here with english translation.