Bhagwad Gita - Post 168

Verse 17

Avibhaktam cha bhooteshu

Vibhaktamiva cha sthitam;

Bhootabhartru cha tajjneyam

Grasishnu prabhavishnu cha.

And undivided, yet He exists as if divided in beings; He is to be known as the supporter of beings; He devours and He generates also.

Avibhaktaṁ ca bhūteṣu : It cannot be divided into parts—some atman here, some atman there. It is one indivisible sea of Selfhood, yet it appears to be divided into little atmans—my atman, your atman, this self, that self, etc. 

Vibhaktam iva ca sthitam: It looks as if it is divided into several atman across many living beings, while actually it is indivisible—like space appearing to be cut into parts when there are vessels containing little spaces. 

Little spaces are not parts of the universal space. There is only one universal space, though it appears as if they are all divided into many vessels in which we cognize this vast space. 

Let us assume for a moment, the sun as Brahman, with its sunshine all pervading.

And each one of us, as various pots.

And the water contained in each pot, each one us, as our mind/intellect.

Though Sunshine pervades the entire creation, it is only when the pot (we) has the mind/intellect (water in a pot), then the sunshine gets reflected on that water.

You remove the water from a pot fully and keep it there, though the sunshine is always there, you won’t see its reflection on the pot in which there is no water. 

Similarly, pure consciousness, though undivided, it still requires conditioned individual beings through whom / in whom, it shines. 

Verse 18 

Jyotishaamapi tajjyotistamasah

Paramuchyate;

Jnaanam jneyam jnaanagamyam

Hridi sarvasya vishthitam.

That, the Light of all lights, is beyond darkness; it is said to be knowledge, the Knowable and the goal of knowledge, seated in the hearts of all.

Jyotiṣām api taj jyotis (13.17): It is the Light of all lights. 

Na tad bhāsayate sūryo (15.6): Thousands of suns cannot stand before it. The light of the sun is like darkness before it. 

Tamasaḥ param: Beyond the darkness of the world shines that supreme radiance of the Absolute. 

Jñānaṁ jñeyaṁ jñānagamyaṁ: It is knowledge, it is the object of knowledge, and it is also the knower. All three clubbed together is that Eternity which is Brahman, the Absolute. 

Hṛdi sarvasya viṣṭhitam: It is in our own heart. We should not be afraid that this tremendous description is of something that is very far away. It is in the heart of all.

Chinmaya writes, 

“If there is an Infinite Light of Knowledge to be known without which life is impossible, in the presence of which alone all experiences can have a meaning and existence --- then this Infinite Goal is certainly to be acquired and possessed. Where am I to seek it? What pilgrimage must I undertake? Am I capable of making an expedition?

Probably, I am not in possession of it today as it must be something to be experienced yonder in some unknown time and place. To negate all such misconceptions, it is boldly declared here that this Infinite dwells in the hearts of all.

Philosophically, "heart" means the area in the mental zone from where noble and pious thoughts spring forth. In an atmosphere of goodness, when the intellect steadily contemplates upon the "Light" that lies beyond darkness --- the Absolute Non-dual Self that exists, transcending all --- but also immanent in its subtle all-pervading nature --- It can be contacted and realized, and therefore, the "heart" is considered as the dwelling place of the Self.”

Love.