After addressing the last question first Pitamah Bheeshma comes to the question of ...what is the supreme goal?

To this he says...he who is supreme radiance , supreme ruler, supreme Brahman.. he is your supreme goal.

And finally he answers the first question...who is the supreme God?

पवित्राणां पवित्रं यो मंगलानां च मंगलम I

दैवतं देवतानां च भूतानां योऽ व्ययः पिता II

He is the most purest , holiest of the holy, he is the most auspicious of the auspicious, he is the God of all Gods, of all the creatures he is the undecaying father, he is the origin, holy rivers are holy because of him, he removes spiritual ignorance. He says having done the churning of all the shastras and having deliberated on them again and again...what is the firm conclusion? meditate on "Narayan Hari".

Parashar Bhattar says anything which is pavitram is pavitram because of bhagvat sambandha....whatever is pure is pure because of it is related to the lord...otherwise what is pure?....