We all know that Brahma is the creator of Universe and this is why Universe is also called as Bramhand(universe). But why has he created Bramhand? What was the purpose behind?
Lord created Universe and all living and non living things. But why he created us? What was his need that he want to fulfill from us? Most important question is what he want from us? There must be something that Lord want from us that's why he created us.
Now think, What human possibly can give to Lord. Actually first think what you have that you can offer to Lord. Let's see what you have that you can give to Lord...
- You have life, so you can offer your life to Lord. BUT wait... that life is not your because this life of your is given by Lord to you. So it's Lord's gift to you. So there is no way you can gift life to Lord because it's already Lord's.
- What more you have... Hmm May be money. You can offer Gold, diamonds and other luxuries items to Lord. But wait, It's Lord who created Diamonds, Golds and all other things and gives it to humans. So whatever you have is because of Lord. So It's already of Lord's, not your. Lord use to give those worldly items to their Devotees. You can return those things (luxuries) back to Lord But that won't be any Gift to Lord because you are giving Lord's thing back to Lord. You are not giving your own thing.
So humans are useless to offer anything to Lord. Because whatever humans have is because of Lord. He gave all to humans. Humans himself has nothing.
Now the main question is... What humans can give to Lord?
Answer is very simple. One thing that we can offer to Lord is Love. Only this thing is we have which is our and we can give that to Lord. And this is the only thing that Lord want from us (Nothing else). He don't want your money, land Property or your life. Because these all were given to you by Lord. If he wants those items then why Lord give all those to you. Couldn't he just keep all to himself if Lord really wants those things? He don't want your money but he wants your Love.
Humans can't offer to Lord anything except Love. love is the need of Lord because Lord is Love himself. He Loves us that's why he created us and that's the reason he has given so many things to us And in return He only wants us to be nice. He wants us to become pure soul and walk on path of Dharma. Lord wants that, in which sinless or pure form Lord send you on earth, you return to Lord in the same pure Form.
"Purpose" is an expected reaction for any action (viz. Karma fala). When one acts without interest & concern, there is no purpose.
BG 9.8 - Keeping My nature (prakruti) under control, I create [& destroy] the world of beings again & again; which are helpless under the nature (prakruti)
BG 9.9 - And O Arjuna, those actions (Karma-s) don't bind Me, as I am uninterested & detached to them
Also read Eternal Return.