SB 7.3.21

tatas ta āśiṣaḥ sarvā
 dadāmy asura-puṅgava
martasya te hy amartasya
 darśanaṁ nāphalaṁ mama
Synonyms: 
tataḥ — because of this; te — unto you; āśiṣaḥ — benedictions; sarvāḥ — all; dadāmi — I shall give; asura-puṅgava — O best of the asuras; martasya — of one who is destined to die; te — such as you; hi — indeed; amartasya — of one who does not die; darśanam — the audience; na — not; aphalam — without results; mama — my.
Translation: 
O best of the asuras, for this reason I am now prepared to give you all benedictions, according to your desire. I belong to the celestial world of demigods, who do not die like human beings. Therefore, although you are subject to death, your audience with me will not go in vain.
Purport: 

It appears that human beings and asuras are subject to death, whereas demigods are not. The demigods who reside with Lord Brahmā in Satyaloka go to Vaikuṇṭhaloka in their present bodily constructions at the time of the dissolution. Therefore although Hiraṇyakaśipu had undergone severe austerities, Lord Brahmā predicted that he had to die; he could not become immortal or even gain equal status with the demigods. The great austerities and penances he had performed for so many years could not give him protection from death. This was foretold by Lord Brahmā.