This verse is from the Bhagavad Gita, Chapter 7, Verse 4. It is written in Sanskrit and translates to English as follows:
bhūmir-āpo ’nalo vāyuḥ khaṁ mano buddhir eva cha
ahankāra itīyaṁ me bhinnā prakṛitir aṣhṭadhā ||4||
"Lord Krishna says -
O Arjun! Earth, water, fire, air, sky, mind, intellect and ego - these eight types of nature are mine, and these are the basic powers of the physical world. This whole world is made up of these."
Explanation in detail:
In this verse, Lord Krishna is reminding us that this world which we see - every particle, every element, every experience of it... has originated from His nature.
We think that we are the masters of our body, the creators of our thoughts, but the truth is that we ourselves are a part of the same divine nature.
Here the Lord is describing His "Bhinna Prakriti" - that is, eight types of nature:
Earth, water, fire, air, space, mind, intellect and ego.
These represent not only the external world, but also the entire system within us.
From every particle of the body to every movement of the mind – everything is made up of this Ashtadha Prakriti.