Lord Krsna explained that Brahman is not a concept of the mind, therefore can't be experienced. Since it is so, some people might think that Brahman doesn't exist, therefore Lord Krsna said Brahman is sarvatragam - goes everywhere, obtains everywhere. It pervades like space. Space is a good example as it is all pervading, but space still can't pervade consciousness, but consciousness itself pervades space. When consciousness Brahman is all pervading, therefore acalam - unmovable, since everywhere is Brahman alone, there is no space other than Brahman for it to move to. It is free from spacial limitation. kūtastham - free from modification. Kūta means anvil. An anvil, on which the blacksmith hammers pieces of heated iron into different shapes, remains unchanged. In the same way Brahman manifests into all changes names and forms, but itself remains unchanged. Another meaning of kūtastham is that abides in māyā. Kūta here means false appearance, and kūtastham means that which abides in false appearance which is māyā. The meaning of Brahman here needs to be understood properly. If the usage of preposition "in" is to be understood like water (contained) in a pot (container), that means Brahman is contained in māyā. If Brahman is based upon māyā, it becomes names and forms, one of the objects in the creation. So the meaning here is to be understood like rope obtains in the snake or gold in the chain. Brahman is the very basis, the truth of the kūta - names and forms. As the unchanging basis therefore it is dhruvam - eternal.
Further, what are the mental disposition of those who pursue aksara-brahman and what happens to them? sanniyamya indriyagrāmam - having complete mastery over organs of action, organs of perceiving and the mind. Since the nature of our sense organs is extrovert, we need to have mastery over them, so the mind which backed them up would have inner composure to contemplate upon aksara-brahman. In Katopanisad 2.4.1 "parāñci khāni vyatrṇatsvayambhūḥ tasmāt parāṅ paśyati nāntarātman kaściddhīraḥ pratyagātmānam aikṣad āvrttacakṣuḥ amrtatvam icchan", saying that Īśvara created sense organs which nature is directed outward, look for sense of fulfilment from outside name and form which is non-self. In this manner they are destroying their own master as it were. But some discriminative people who desire limitless, they enquire about the self, following the teaching of śāstra as the means for moksa, turn their eyes inward, seeing this inner-self is the meaning of immortality itself.
Turning senses inward is not easy, hence one must have lived a disciplined and contented life when one in the karma-yoga stage, then change of direction on the senses is possible here. One also cultivates certain values and attitude which will bring about equanimity towards all beings - sarvatra sama-buddhayah. With regard to their responses they are sarva-bhūta-hite ratāh - those who care of well being of all beings.
The knowers of nirguna-brahman reach Īśvara alone - te prāpnuvanti mām eva. Reaching here has no gap either in time-wise or space wise. Because the obtainer and the obtained is one and the same. Only not knowing separates them. Lord Krsna already said, "my vision is that the one who knows (me), however, is indeed myself" (Gītā verse 7.18).