so basically answer the question

Why does one have to be greater then the other,

Both are required for the Sikh way of life

Naam is the essence of bani. Bani praises the Naam.

so from our prespective, it is Naam.

but how could we know Naam without (Gur)Bani?

so can we even sperate the two?

But gurbani has its Source. And Naam Is The Source.

So its not a question of which is better. If Naam is the nectar than Gurbani is the flower or the petals of the flower.

Gurbani is Guru. Naam is God Itself, Guru and Gurubani and Chayla. Naam is everything.

Guru forgive me mistakes.

Gurbani has not done a comparison of Naam and Gurbani though it has mentioned them separately. This comparison should not be thought of. Gurbani is Guru and as such is the source of Naam. Since Naam has come out of mouth of Satguru, therefore Naam too is a form of Gurbani but this does not mean that Naam should not be recited on top of Gurbani paath or Gurbani Kirtan.

The ultimate reality will be realized through Naam only but to reach that stage of Naam Abhyaas we need to do paath of Gurbani and do kirtan of Gurbani. In Gurmat Bibek book of Bhai Sahib it's written that in olden days people used to go in seclusion to bring the mind under control but there is no better place to bring mind under control that Akhand Kirtan and Akhand Paath Sahib. No matter how much the mind is wandering around and running around, if one attempts to focus mind on Naam at Akhand Kirtan Samagam of Siri Akhand Paath Sahib samagam, it comes under control without much effort. Such is the paaras kala of Gurbani.

The key is the more paath we do, more Naam abhyaas we can do. The Naam khanda starts vibrating with full vigour when one does a lot of Gurbani paath. This proves the efficacy of Gurbani paath, when it comes to controlling mind and trying to focus it on Naam.

Such thought as to what is greater should not arise in a Gursikh's mind. Both are important and the essence of both is same. Here is a Gurbani pankiti that tells us that hearing Gurbani the dirt of mind is cleansed and Gurbani gets Naam to reside in one's heart:

ਗੁਰਬਾਣੀ ਸੁਣਿ ਮੈਲੁ ਗਵਾਏ ॥ ਸਹਜੇ ਹਰਿ ਨਾਮੁ ਮੰਨਿ ਵਸਾਏ ॥1॥

Gurbani is very loving to Guru Sahib and Guru Sahib has called it "Hamari Pyaari, Amritdhaari...|| (Gurbani is our beloved and its full of Amrit). In Gurbani is Amrit all over (...Vich Baani Amrit saare).

Kulbir Singh