In Bhagwadgita, Krishna said to Arjun that if one worships other Devas, he will go to their Loka but who worships and surrenders unto him, will get united with him.
But when I read Mahabharat, I found that Krishna advised Arjun to please Siva for Pasupatastra. Similarly, Krishna advised Arjun to take blessings of Goddess before Mahabharat war.
I am a bit confused on this. When Krishna was himself with Arjun, why he needed Pasupatastra and other Astras from other Devas?