B.G 8.05

अन्तकाले च मामेव स्मरन् मुक्त्वा कलेवरम्। यः प्रयाति स मद्भावं याति नास्त्यत्र संशयः ॥५॥

Whoever, at the time of death, remembering Me alone, becomes free from this body, attains divine existence in Me. Of this, there is no doubt.

Gīta Bhāshya 8.05

Attaining 'madbhāvaṁ', means attaining permanent existence in the Lord.

मद्भावं मयि सत्ताम्। निर्दुःखनिरतिशयानन्दात्मिकाम्। तच्चोक्तम्-

'My nature' (madbhāvaṁ) means existence in Me. It is without sorrow and of the nature of supreme bliss. Also, it has been said:

"मुक्तानां च गतिर्ब्रह्मन् क्षेत्रज्ञ इति कल्पितः।"

"The destination of the liberated is considered to be the Brahman, that kṣetrajña, the knower of the field."

इति मोक्षधर्मे ॥५॥

- stated thus in the Mokṣa-dharma section (of Mahabharata).

Gīta Tātparya 8.05

Remembering the Lord at the time of death is possible only for those who have mastered the ability to be absorbed in Him all the time through constant remembrance.

मद्भावं मयि भावम्। सदा तद्भावभावितानामेव स्मरंस्त्यजतीति केवलं तत्कालस्मरणं भवति। न चेत् स्मरतोऽपि समाधिस्थस्खलनवत् पूर्वकर्मानुसारिस्मृत्या तत्प्राप्तिरेव भवति। अपरोक्षज्ञानिनां प्रारब्धकर्मावसाने स्मरंस्त्यजतीति भवत्येव। 'प्रयाणकालेपि च मां ते विदुः'-इत्युक्तत्वात्। 'युक्तचेतसः' इति विशेषणात् नित्यं स्मरतामेव अपरोक्षज्ञानं जायते।

My state (madbhāvaṁ) means existence in Me. Only for those who are always absorbed in that state it is possible to depart remembering Me. Therefore, mere remembrance at the final moment is not possible. Even if one tries, he fails, like a fall from meditation, due to memory following past karma. Hence, only attainment according to past karma occurs. For those with direct knowledge, at the end of their operative karma, remembering Me while departing certainly happens. Because it has been said, 'Even at the time of departure, they know Me(7-30).' From the qualifier 'those whose minds are absorbed (7-30),' it follows that direct knowledge arises only for those who remember Me constantly.

"भक्त्या ज्ञानात् निषिद्धानां त्यागात् नित्यम् हरिस्मृतेः। अरागात् विहितात्यागादित्येतैरेव संयुतैः। अपरोक्षदर्शनं विष्णोर्जायते नान्यथा क्वचित्॥"

"Direct vision of Vishnu arises only through devotion, knowledge, abstaining from prohibited actions, constant remembrance of Hari, detachment, and renouncing the fruits of prescribed actions. It never arises in any other way."

इति सत्तत्त्वे ॥५॥

-stated thus is Sattvata samhita (one of the earliest Pancharatra āgamas).