In plain words
From anger comes delusion; from delusion, loss of memory; from loss of memory, destruction of buddhi; and when buddhi is destroyed, one is lost.
Word for word
From anger comes delusion; from delusion, confusion of memory; from the failing of memory, the ruin of buddhi; from the ruin of buddhi, one perishes.
क्रोधाद् भवति सम्मोहः सम्मोहात् स्मृतिविभ्रमःस्मृतिभ्रंशाद् बुद्धिनाशो बुद्धिनाशात् प्रणश्यति
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam· bhāṣya
क्रोधात् भवति संमोहः अविवेकः कार्याकार्यविषयः । क्रुद्धो हि संमूढः सन् गुरुमप्याक्रोशति । संमोहात् स्मृतिविभ्रमः शास्त्राचार्योपदेशाहितसंस्कारजनितायाः स्मृतेः स्यात् विभ्रमो भ्रंशः स्मृत्युत्पत्तिनिमित्तप्राप्तौ अनुत्पत्तिः । ततः स्मृतिभ्रंशात् बुद्धिनाशः बुद्धेर्नाशः । कार्याकार्यविषयविवेकायोग्यता अन्तःकरणस्य बुद्धेर्नाश उच्यते । बुद्धिनाशात् प्रणश्यति । तावदेव हि पुरुषः यावदन्तःकरणं तदीयं कार्याकार्यविषयविवेकयोग्यम् । तदयोग्यत्वे नष्ट एव पुरुषो भवति । अतः तस्यान्तःकरणस्य बुद्धेर्नाशात् प्रणश्यति पुरुषार्थायोग्यो भवतीत्यर्थः ॥ ६३ ॥
In plain words
'From anger, delusion arises' — meaning, the loss of any ability to tell right action from wrong. Someone in the grip of anger, confused as he is, will even revile his own teacher. 'From delusion, memory becomes confused' — the memory built up from the teachings of scripture and teacher simply falters; even when the moment calls for that memory to surface, it fails to arise. And once memory fails like that, 'understanding is destroyed' — meaning, the mind loses its very capacity to tell right action from wrong. 'From the destruction of understanding, he perishes' — because a person is, in a real sense, only as much as his mind's capacity to discern right from wrong; once that capacity is gone, the person is, for all practical purposes, lost. That is why, once his mind's understanding collapses, he perishes — becomes unfit for anything worth pursuing in life. That is the meaning.
Close to the Sanskrit
'From anger arises delusion' — non-discrimination concerning what should and should not be done. For, being angered, being deluded, one reviles even one's own teacher. 'From delusion, confusion of memory' — of memory produced from the impressions instilled by the teaching of scripture and teacher, there would be confusion, a lapse — that is, non-arising, even when the occasion for memory's arising presents itself. Then, from the lapse of memory, 'destruction of understanding' — destruction of understanding. The unfitness of the mind, of the understanding, for discrimination concerning what should and should not be done, is called 'destruction of understanding.' 'From the destruction of understanding, he perishes' — for a person exists precisely to the extent that his mind is fit for discrimination concerning what should and should not be done; when that becomes unfit, the person becomes, precisely, lost. Therefore, from the destruction of his mind's, his understanding's, [capacity], he perishes — becomes unfit for the ends of human life: such is the meaning. [End of commentary on verse 63.]