Though many sages have tried to describe God and his purpose, the best they could do was to declare neti, neti (not this, not this).
Agreed. Can you do any better?
Behind this facade, there must be a grand purpose—something which religious leaders could not understand.
Why must there be a grand purpose? Why are you eliminating a regular purpose, and petty pupose, no purpose at all, God isn't any all like what religious people think of him as or that it might not exist?
You use the word SCIENCE as if it is an ultimate weapon near which no one can come talking about intuition. Even Einstein has gone on record saying intuition preceded most of his scientific accomplishments!
For an intuitive mind, whether it is the individual human body or the larger cosmic body, essentially, they are made of five elements – earth, water, fire, air and space.
Anytime anyone uses an Einstein quote to support wrong notions or religious notions or to suggest religion and science are similar, you can be sure that person doesn't understand science, religion or Einstein.