B.G 13.19
iti kṣetraṃ tathā jñānaṃ jñeyaṃ coktaṃ samāsataḥ। madbhakta etadvijñāya madbhāvāyopapadyate ॥19॥
Thus, the field, knowledge, and the knowable have been described briefly. My devotee, by understanding this, attains the ability to feel my presence within.
Gīta Bhāshya 13.19
At first, when the practitioner is still of a distorted nature, the means to be employed was instructed. The current verse describes the effect of devoutly employing such means.
vikārāntarbhāvāt jñānasādhanaṃ prathamataḥ uktam। bahutvāt sādhanātyupayogāt prabhāvaḥ ॥19॥
At first, because of distorted nature, the means of knowledge was spoken. The effect arises from the use of means with excessive striving.
Gīta Tātparya 13.19
'madbhāvāya' - capacity to perceive or feel of my state within.
madbhāvāya mayi bhāvāya ॥19॥
The word 'madbhāvāya' is split into 'mayi bhāvāya', i.e. the feeling of my state within.