Bhagavad Gita · Dhyana Yoga (Atma-samyama Yoga)Chapter 6, Shloka 40 (6.40)

"Tāta" — a word of affection. Shankara: tanoti ātmānaṃ putra-rūpeṇeti pitā tāta ucyate, pitaiva putra iti putro'pi tāta ucyate, śiṣyo'pi putra ucyate — the father extends himself in the form of the son, so he is called "tata"; the father is the son, so the son too is called "tata"; and a disciple too is called a son. Here Krishna addresses Arjuna like a son / a dear disciple.

Shankaracharya. Nāśo nāma pūrvasmāt hīna-janma-prāptiḥ sa yoga-bhraṣṭasya nāsti — "destruction" means obtaining a lower birth than before — this does not happen to one who has fallen from yoga; kalyāṇa-kṛt śubha-kṛt.

Acharya Ramanuja. Śraddhayā yoge prakrāntasya tasmāt pracyutasya iha ca amutra ca vināśaḥ na vidyate — for one who began yoga with faith and fell away from it, there is no destruction here or there; destruction has two forms — abhilaṣitānavāpti-rūpaḥ (not getting what one wanted) and pratyavāyākhyaḥ aniṣṭāvāpti-rūpaḥ (getting what is unwanted) — neither occurs; na hi niratiśaya-kalyāṇa-rūpa-yoga-kṛt kaścit kāla-traye api durgatiṃ gacchati — no one who practises yoga, the highest good, comes to a bad end in any of the three times.